Internet Glossary

404 Error

File not found. This error happens when a user requests a page that is no longer present. This can be caused if the file has been moved, deleted or renamed.

Ad Inventory

The number of page views a site has available for advertising.

Adult Words

Words that are censored by search engines. These include the FCC's seven forbidden words. Search engines often maintain two databases, to allow a user to search all data or to filter offensive results.

Agent Name Delivery

The process of sending search engine spiders to a tailored page, yet directing your visitors to what you want them to see. This is done using Server Side includes (or other dynamic content techniques). SSL, for example, can be used to deliver different content to the client depending on the value of https_USER_AGENT. Most normal browser software packages have a user agent string which starts with "Mozilla". Most search engine spiders have specific agent names, such as "Scooter", "Googlebot", "Lycos spider" and "Slurp".


A set of rules that a search engine uses to rank the listings contained within its index, in response to a particular query. No search engine reveals exactly how its own algorithm works, to protect itself from competitors and those who wish to spam the search engine. (it is the mathematical program formula used to determine which web pages are displayed in search results and what order).

Algorithmic Results; see Organic Listings.


A popular search engine.  AllTheWeb is the main search engine for FAST available at


A popular search engine, available at


An HTML "tag" that allows a browser to display text instead of a graphic. Some search engines read these tags in order to help with rankings. All images can be given an ALT tag.

AOL Netfind

The default search engine for users of the AOL Internet service provider, and thus a busy site.

Apache Web Server

The leading web server software of the Internet. Apache is an open source project.


A small program, often written in Java, which usually runs in a web browser, as part of a web page. It is possible that the use of such a program may cause spiders and robots to stop indexing a page.

Ask Jeeves

A Meta search engine which can be asked questions in common English  (httpss://


Active Server Pages, a server based scripting language that is used to provide dynamic content and build database driven web sites where the browser may not have any scripting.


All the links pointing at a particular web page. Also called inbound links. Source: Webmaster World Forums


When pages are removed from a search engine's index specifically because the search engine has deemed them to be spamming or violating some type of guidelines.


It started out as referring to specific content management software (blogger), and has transitioned into a description for a wide range of personal pages, journals, and diary type setups.

Boolean search

A search allowing the inclusion or exclusion of documents containing certain words through the use of operators such as AND, NOT and OR.


Best of Web, a reference to one search engine that classifies its core set of sites as "the best of web". BOW is also used as a reference to the BOW TIE theory. It states that the core of the web is a central hub with two off shoots extending in either direction. A graphical map of that theory appears to look like a Bow Tie.


IP Addresses are 4 digits between 0 and 255. (Example:111.222.333.233). Each number represents a "class" that is most often denoted as A-C (Example: aaa.bbb.ccc.ddd).  A "c-class"refers to the 255 addresses from "" to "".


Common Gateway Interface - a standard interface between web server software and other programs running on the same machine. In practice, CGI programs are used to handle forms and database queries on web pages, and to produce non-static web page content.

Clickthrough Rate

The percentage of those clicking on a link out of the total number who see the link. For example, imagine 10 people do a web search. In response, they see links to a variety of web pages. Three of the 10 people all choose one particular link. That link then has a 30 percent clickthrough rate. Also called CTR.


A computer, program or process which makes requests for information from another computer, program or process. Web browsers are client programs. Search engine spiders are (or can be said to behave as) clients.


In terms of search engine marketing, this is the act of getting a search engine to record content for a URL that is different than what a searcher will ultimately see. (Hiding of page content). It can be done in many technical ways. Several search engines have explicit rules against unapproved cloaking. Those violating these guidelines might find their pages penalized or banned from a search engine's index. As for approved cloaking, this generally only happens with search engines offering paid inclusion program. Anyone offering cloaking services should be able to demonstrate explicit approval from a search engine about what they intend to do. If not, then they should then have explained the risks inherent of unapproved cloaking. (Using cloaking a web site will submit a page built purely to rank high for a search engine algorithm and then display completely different content for human users).


The listing of only one page from each web site in a search engine or a directory's list of search results. This avoids occupation of all the top results of a query by a small number of web sites and provides a cleaner more useful list of results to the user.

Cold Fusion

A CGI database program from Allaire. Cold fusion uses a file extension of cf or cfm. Also used by some cloaking programs.


The HTML <-- and --> tags are used to hide text from browsers. Some search engines ignore text between these symbols but others index such text as if the comment tags were not there. Comments are often used to hide JavaScript code from non-compliant browsers, and sometimes to provide invisible keywords to some search engines.

Concept search

A search for documents related conceptually to a word, rather than specifically containing the word itself.

Contextual Link Inventory

To supplement their business models, certain text-link advertising networks have expanded their network distribution to include "contextual inventory". Most vendors of "search engine traffic" have expanded the definition of Search Engine Marketing to include this contextual inventory. Contextual or content inventory is generated when listings are displayed on pages of Web sites (usually not search engines), where the written content on the page indicates to the ad-server that the page is a good match to specific keywords and phrases. Often this matching method is validated by measuring the number of times a viewer clicks on the displayed ad.

Conversion Rate

The relationship between visitors to a web site and actions consider to be a "conversion," such as a sale or request to receive more information. Often expressed as a percentage. If a web site has 50 visitors and 10 of them convert, then the site has a 20 percent conversion rate.

Cost Per Click

System where an advertiser pays an agreed amount for each click someone makes on a link leading to their web site. Also known as CPC.


A counter counts hits or page views to a web site. Counter quality and features can vary widely. Most common are image tag counters that are activated when anyone views a page with the graphics enabled.

CPC; see Cost Per Click.


System where an advertiser pays an agreed amount for the number of times their ad is seen by a consumer, regardless of the consumer's subsequent action. Heavily used in print, broadcasting and direct marketing, as well as with online banner ad sales. CPM stands for "cost per thousand," since ad views are often sold in blocks of 1,000. The M in CPM is Latin for thousand.


Component of search engine that gather listings by automatically "crawling" the web. A search engine's crawler (also called a spider or robot), follows links to web pages. It makes copies of the web pages found and stores these in the search engine's index.

Cross Browser

A reference to "Cross Browser" is usually in relation to java script, html, or css code that can work in multiple browsers.

Cross Linking

Cross linking is linking across content within the same site.

CTR; see Clickthrough Rate.

Dead Link

An Internet link which doesn't lead to a page or site, probably because the server is down or the page has moved or no longer exists.

Deep Linking

Linking to content buried deep within a web site. The link is referred to as "deep" because it is often linked to content found two or more directories deep within a web site.


When pages are removed from a search engines index. This may happen because they have been banned or for other reasons, such as an accidental glitch on the search engine's part.


Descriptive text associated with a web page and displayed, usually with the page title and URL, when the page appears in a list of pages generated by a search engine or directory as a result of a query. Some search engines take this description from the DESCRIPTION Meta tag – others generate their own from the text in the page. Directories often use text that was provided at registration.

Direct Hit

A system which monitors the search engine users' selections from search engine results, counting which results are clicked on most, and how long visitors spend at that site. This is done so as to improve the relevancy of search results.


A type of search engine where listings are gathered through human efforts, rather than by automated crawling of the web. In directories, web sites are often reviewed, summarized in about 25 words and placed in a particular category.

DNS Lookup

Sometimes referred to as Reverse Domain Name Server Lookup. Most often used by webmasters while looking at server log files. It converts a unique IP address of a site visitor to its domain name.


A Meta search engine. Found at httpss://


An Internet address. The most significant part of the address comes at the end. Typical top-level domains are .com, .edu, .gov, .org. There are also various geographic top-level domains (e.g, .ar, .ca, .fr, .ro, etc.)

Doorway Page

A web page created expressly in hopes of ranking well for a term in a search engine's non-paid listings and which itself does not deliver much information to those viewing it. Instead, visitors will often see only some enticement on the doorway page leading them to other pages (i.e., "Click Here To Enter), or they may be automatically propelled quickly past the doorway page. With cloaking, they may never see the doorway page at all. Several search engines have guidelines against doorway pages, though they are more commonly allowed in through paid inclusion programs. Also referred to as bridge pages, gateway pages and jump pages, among other names.

Dynamic Content

Information on web pages that change or is changed automatically, e.g. based on database content or user information. Sometimes it's possible to spot that this technique is being used, e.g. if the URL, ends with .asp, .cfm, .cgi or .shtml. It is possible to serve dynamic content using standard (normally static) .htm or .html type pages, though Search engines will currently index dynamic content in a similar fashion to static content, although they will not usually index URLs which contain the "?" character.

Dynamic IP Address

An IP address that changes each time you connect to the Internet.

Entry Page

Sometimes refers to a single page with a logo and "click here" link to enter.


Earnings per Click.


Earnings per Visitor.


Previously a popular search engine with its own database, it has now been transformed into a popular Meta search engine. Available at httpss://


Free For All links. These are places that allow anyone to add a link. Search engines do not endorse FFA and ignore them. FFA has become one of the biggest sources of email addresses for spammers.


An HTML technique for combining two or more separate HTML documents within a single web browser screen. A framed web site often causes great problems for search engines, and may not be indexed correctly.

Frequency Cap

The maximum number of times or length of times a site visitor will be shown the same or related advertisement.

Full-text Index

An index containing every word of every document cataloged, including Stop Words.

Fuzzy search

A search that will find matches even when words are only partially spelled or misspelled.

Gateway Page

A web page submitted to a search engine (spider) to give the relevance-algorithm of that particular spider the data it needs, in the format that it needs it, in order to place a site at the proper level of relevance for the topic(s) in question.

A failed search engine owned by Disney, that has now become a portal for their media properties (Disney, ABC, ESPN). Its search is now provided by Overture.


The previous name of Overture, which operates a "pay-per-click" scheme where web sites can pay to increase their hierarchy. The URL is httpss://

Graphical Search Inventory. Banners, and other types of advertising units which can be synchronized to search keywords. Includes pop-ups, browser toolbars and rich media.


Many search engines give extra weight and importance to the text found inside HTML heading sections. It is generally considered good advice to use headings when designing web pages and to place keywords inside headings.

Hidden Text

Text on a web page which is visible to search engine spiders but not visible to human visitors. This is sometimes because the text has been set the same color as the background. Hidden text is often used for spamdexing. Many search engines can now detect the use of hidden text, and often remove offending pages from their database or lower such pages' positioning.


In the context of visitors to web pages, a hit (or site hit) is a single access request made to the server for either a text file or a graphic. If, for example, a web page contains ten buttons constructed from separate images, a single page will involve eleven hits on the server. In the context of a search engine query, a hit is a measure of the number of web pages matching a query returned by a search engine or directory.


A search engine converted into a Meta search engine that displays results from Google, Teoma, Inktomi and Fast. The URL is httpss://


HyperText Markup Language – the (main) language used to write web pages.

Image Map

A set of hyperlinks attached to areas of an image. This may be defined within a web page, or as an external file.

Inbound Link

A hypertext link to a particular page from elsewhere, bringing traffic to that page. Inbound links are counted to produce a measure of the page popularity. Searches for inbound links to a page can be made on Altavista, Google and Hotbot.


The collection of information a search engine has that searchers can query against. With crawler-based search engines, the index is typically copies of all the web pages they have found from crawling the web. With human-powered directories, the index contains the summaries of all web sites that have been categorized.


A failed search engine that now redirects its traffic to The URL is httpss://


The database of web sites used by some of the largest search engines. Owned by

IP Address

Whenever you connect to the Internet, you are giving a unique 4 number Internet Protocol Address (IP Address). Your IP address is how data finds its way back and forth from your computer to a particular web site. Your IP address may change each time you attach to your ISP. If your IP address stays the same from connection to connection, you are said to have a static IP address. If it changes each time you connect, you are said to have a dynamic IP address. IP addresses can be important in the context of search engine submission because some search engines have been known to ignore submissions from any one IP over a certain limit.

IP Deliver

Similar to agent name delivery; this technique presents different content depending on the IP address of the client. It is very difficult to view pages hidden using this technique, because the real page is only visible if your IP address is the same as (for example) a search engine's spider.


A computer programming language whose programs can run a on a number of different types of computers and/or operating systems. Used extensively to produce applets for web pages.


A simple interpreted computer language used for small programming tasks within HTML web pages. The scripts are normally interpreted (or run) on the client's computer by the web browser. Some search engines have been known to index these scripts, presumably erroneously.


A word which forms (part of) a search engine query.

Keyword Density

A property of the text in a web page which indicates how close together the keywords appear. Some search engines use this for positioning. Analyzers are available which allow comparisons between pages. Pages can then be produced with similar keyword densities to those found in high ranking pages.

Keyword Domain Name

The use of keywords as part of the URL to a web site. Positioning is improved on some search engines when keywords are reinforced in the URL.

Keyword Phrase

A phrase which forms (part of) a search engine query.

Keyword Purchasing

The buying of search keywords from search engines. Overture is the main seller of keywords.

Keyword Search

A search for documents containing one or more words that are specified by a user.

Keyword Stuffing

The repeating of keywords and keyword phrases in META tags or elsewhere.

Landing Page

The specific web page that a visitor ultimately reaches after clicking a search engine listing. Marketers attempt to improve conversion rates by testing various landing page creative, which encompasses the entire user experience including navigation, layout and copy.


A count of the number of links pointing (inbound links) at a web site and links pointing out (outbound links). Many search engines now count linkage in their algorithms.

Link Farm

Free for All links. These are places that allow anyone to add a link and are viewed as spam by the search engines.


A reference to when URLs are removed and the URL goes 404.

Link Popularity

A raw count of how "popular" a page is based on the number of backlinks it has. It does not factor in link context or link quality, which are also important elements in how search engines make use of links to impact rankings.

Link Text

The text that is contained within a link. For example, search engine is a link that contains the link text "search engine."


The information that appears on a search engine's results page in response to a search.

Log File

Files maintained on a server in which details of all file accesses are stored. Analyzing log files can be a powerful way to find out about a web site's visitors, where they come from and which queries are used to access a site. Various software packages are available to analyze log files.


A program that logs web page views. Most often a logger will also track referrals.


A directory. The URL is httpss://


A search engine. The URL is


A Meta search engine found at Results from various search engines are summarized in an easy to read form.


A Eeta search engine found at

Meta Search

A search of searches. A query is submitted to more than one search engine or directory, and results are reported from all the engines; possibly after removal of duplicates and sorting. Also the Meta search engine of the same name found at

Meta Search Engine

A search engine that gets listings from two or more other search engines, rather than through its own efforts.

Meta Tags

Information placed in a web page not intended for users to see but instead which typically passes information to search engine crawlers, browser software and some other applications.

Meta Description Tag

Allows page authors to say how they would like their pages described when listed by search engines. Not all search engines use the tag.

Meta Keywords Tag

Allows page authors to add text to a page to help with the search engine ranking process. Not all search engines use the tag.

Meta Robots Tag

Allows page authors to keep their web pages from being indexed by search engines, especially helpful for those who cannot create robots.txt files. The Robots Exclusion page provides official details.

Mirror Sites

Multiple copies of web sites or web pages, often on different servers. The process of registering these multiple copies with search engines is often treated as spamdexing because it artificially increases the relevancy of the pages. Filters now automatically remove many of these mirrors from the indexes.


People quite often spell words incorrectly when using search engines. Pages which use common misspellings will often receive extra hits, so it is a useful technique to include common misspellings of words in ALT tags, keywords, page names and titles. A similar effect occurs when spaces are missed out and words are accidentally joined together.

Multiple Domain Names

The use of several extra domains to provide gateway pages or gateway sites to the main site.

Northern Light

A search engine with a "pay to access" collection of business, health and consumer publication articles. The URL is


The act of misrepresenting Meta tags or content. The user is presented with a page that looks normal, but it is not the page submitted to search engines. This is similar to cloaking or stealth pages, but it further protects the code by giving code stealers a Mickey page. The page often looks normal, but there will be something wrong with it to cause it to rank low on search engines (things like bad keyword density or Meta tag errors). When someone steals a high ranking page like this and installs it on their own server, they will never get the rankings the real page gets.

Organic Listings

Listings that search engines do not sell (unlike paid listings). Instead, sites appear solely because a search engine has deemed it editorially important for them to be included, regardless of payment. Paid inclusion content is also often considered "organic" even though it is paid for. This is because that content usually appears intermixed with unpaid organic results.

Outbound Links

Links on a particular web page leading to other web pages, whether they are within the same web site or other web sites.

Paid Inclusion

Advertising program where pages are guaranteed to be included in a search engine's index in exchange for payment, though no guarantee of ranking well is typically given. For example, LookSmart is a directory that lists pages and sites, not based on position but based on relevance. Marketers pay to be included in the directory, on a CPC basis or per-URL fee basis, with no guarantee of specific placement. Also see XML Feeds.

Paid Listings

Listings that search engines sell to advertisers, usually through paid placement or paid inclusion programs. In contrast, organic listings are not sold.


Term popularized by some search engines as a synonym for pay-per-click, stressing to advertisers that they are only paying for ads that "perform" in terms of delivering traffic, as opposed to CPM-based ads, where ads cost money, even if they don't generate a click.

Pay-Per-Click; see Cost Per Click.

Paid Placement

Advertising program where listings are guaranteed to appear in response to particular search terms, with higher ranking typically obtained by paying more than other advertisers. Paid placement listings can be purchased from a portal or a search network. Search networks are often set up in an auction environment where keywords and phrases are associated with a cost-per-click (CPC) fee. Overture and Google are the largest networks, but MSN and other portals sometimes sell paid placement listings directly as well. Portal sponsorships are also a type of paid placement.


The process of ordering web sites or web pages by a search engine or a directory so that the most relevant sites appear first in the search results for a particular query. Software can be used to determine how a URL is positioned for a particular search engine when using a particular search phrase.

Positioning Technique

A method of modifying a web page so that search engines (or a particular search engine) treat the page as more relevant to a particular query (or a set of queries).


Stands for pay-per-click and means the same as cost-per-click.


A word, a phrase or a group of words, possibly combined with other syntax used to pass instructions to a search engine or a directory in order to locate web pages.


A search where a user instructs an engine to find more documents that are similar to a particular document. Also called "find similar".

Rank or Ranking

How well a particular web page or web site is listed in a search engine results. For example, a web page about apples may be listed in response to a query for "apples." However, "rank" indicates where exactly it was listed -- be it on the first page of results, the second page or perhaps the 200th page. Alternatively, it might also be said to be ranked first among all results, or 12th, or 111th. Overall, saying a page is "listed" only means that it can be found within a search engine in response to a query, not that it necessarily ranks well for that query. Also called position or positioning. (in the context of search engines, it is the position that a sites entry is displayed in a search engine query results).

Reciprocal Link

A link exchange between two sites.


The URL of the web page from which a visitor came. The server's referrer log file will indicate this. If a visitor came directly from a search engine listing, the query used to find the page will usually be encoded in the referrer URL, making it easy to see which keywords are bringing visitors. The referrer information can also be accessed as document referrer within JavaScript or via the https_REFERER environment variable (accessible from scripting languages).

Refresh Tag

Meta Refresh tag reloads a page at a set time.


How well a document provides the information a user is looking for, as measured by the user.

Relevancy Algorithm

The method a search engine or directory uses to match the keywords in a query with the content of each web page, so that the web pages found can be ordered suitably in the query results. Each search engine or directory is likely to use a different algorithm, and to change or improve its algorithm from time to time.

Registration; see Submission.

Results Page

After a user enters a search query, the page that is displayed, is call the results page. Sometimes it may be called SERPs, for "search engine results page." Source: Webmaster World Forums


Any browser program which follows hypertext inks and accesses web pages but is not directly under human control. Examples are the search engine spiders, the "harvesting" programs which extract e-mail addresses and other data from web pages and various intelligent web searching programs.


A text file stored in the top level directory of a web site to deny access by robots to certain pages or sub-directories of the site. Only robots which comply with the Robots Exclusion Standard will read and obey the commands in this file. Robots will read this file on each visit, so that pages or areas of sites can be made public or private at any time by changing the content of robots.txt before re-submitting to the search engines.


Stands for "Return On Investment" and refers to the percentage of profit or revenue generated from a specific activity. For example, one might measure the ROI of a paid listing campaign by adding up the total amount spent on the campaign (say $200) versus the amount generated from it in revenue (say $1,000). The ROI would then be 500 percent. Or often referred to sales per lead.


RON: Run of Network. Large advertising brokers can sell ads across the entire network of member sites.


ROS: Run of Site. An ad that can be placed anywhere on a web site without restrictions.


The name of the Altavista search engine's spider.

Search Engine

The software that searches an index and returns matches. Search engine is often used synonymously with spider and index, although these are separate components that work with the engine. Some of the major search engines are AltaVista, Google, Teoma, and AllTheWeb. Note: that Yahoo is a directory, not a search engine. The term Search Engine is also often used to describe both directories and search engines.

Search Engine Marketing

The act of marketing a web site via search engines, whether this be improving rank in organic listings, purchasing paid listings or a combination of these and other search engine-related activities.

Search Engine Optimization

The act of altering a web site so that it does well in the organic, crawler-based listings of search engines. In the past, has also been used as a term for any type of search engine marketing activity, though now the term search engine marketing itself has taken over for this. Also called SEO.

Search Terms

The words (or word) a searcher enters into a search engine's search box. Also used to refer to the terms a search engine marketer hopes a particular page will be found for. Also called keywords, query terms or query.


Acroymn for search engine marketing and may also be used to refer to a person or company that does search engine marketing (i.e.., "They're an SEM firm).


Search Engine Marketing Professional Organization, a non-profit, formed to increase the awareness of and educate people on the value of search engine marketing.


Acronym for search engine optimization and often also used to refer to a person or company that does search engine optimization (i.e., "They do SEO").


Short for "Search Engine Results Page". This is the page that is generated by a search engine in response to a search query.


A computer, program or process which responds to requests for information from a client. On the Internet, all web pages are held on servers. This includes those parts of the search engines and directories which are accessible from the Internet.

Server Side Includes

A means of creating a 'template' web page, which places some standard text in a set of web pages or applies a consistent appearance across a set of web pages.


The use of various means to steal another site's traffic. Techniques used include the wholesale copying of web pages (with the copied page altered slightly to direct visitors to a different site, and then registered with the search engines) and the use of keywords or keyword phrases "belonging" to other organizations, companies or web sites.

Shopping Search

Shopping search engines allow shoppers to look for products and prices in a search environment. Premium placement can be purchased on some shopping search indices.


The name of the spider used by Inktomi.


Any search engine marketing method that a search engine deems to be detrimental to its efforts to deliver relevant, quality search results. Some search engines have written guidelines about what they consider to be spamming, but ultimately any activity a particular search engine deems harmful may be considered spam, whether or not there are published guidelines against it. Example of spam include the creation of nonsensical doorway pages designed to please search engine algorithms rather than human visitors or heavy repetition of search terms on a page (i.e. the search terms are used tens or hundreds or times in a row). These are only two of many examples. Determining what is spam is complicated by the fact that different search engines have different standards. A particular search engine may even have different standards of what's allowed, depending on whether content is gathered through organic methods versus paid inclusion. Also referred to as spamdexing.


See spam.

Spider, Spyder

That part of a search engine which surfs the web, storing the URLs and indexing the keywords and text of each page it finds.


The process of surfing the web, storing URLs and indexing keywords, links and text. Typically, even the largest search engines cannot spider all of the pages on the net. This is due to the huge amount of data available, the speed at which the new data appears, the use of politeness windows and practical limits on the number of pages that can be visited in a given time. The search engines have to make compromises in order to visit as many sites as possible, and they do this in different ways. For example some only index the home pages of each site, some only visit sites they're explicitly told about, and some make judgments about the importance of sites (from number and quality of inbound links) before "digging deeper" into the subpages of a site.

Splash Page

Similar to a gateway page but provides an initial display which must be viewed before a visitor reaches the main page. This usually acts as a kind of "opening title" sequence, and can be extremely annoying.


Server Side Includes. Used (for example) to add dynamically generated content to a web page.

Stealth Script

A CGI script which switches page content depending on who or what is accessing the page.


The ability for a search to include the "stem" of words. For example, stemming allows a user to enter "swimming" and get back results also for the stem word "swim".

Stop Word

A word which is ignored in a query because the word is so commonly used that it makes no contribution to relevancy. Examples are, common net words such as computer and web, and general words like get, I, me, the, and you.


The act to submitting a URL for inclusion into a search engine's index. Unless done through paid inclusion, submission generally does not guarantee listing. In addition, submission does not help with rank improvement on crawler-based search engines unless search engine optimization efforts have been taken. Submission can be done manually (i.e., you fill out an online form and submit) or automated, where a software program or online service may process the forms behind the scenes. Useful to get listed with many of the minor search engines, but don't reply on such services to get listed with the major search engines. Many of these services are automatic and run from web sites. Others run offline. Some are free. Beware of supplying your email address to the so called FFA (free for all) services – you may receive lots of spam.


Top Level Domain. This is the far right portion of any domain name. Examples: .com, .org, .uk, .net.


The visitors to a web page or web site. Also refers to the number of visitors, hits, accesses, etc., over a given period.


The Lycos spider.

Unique Visitor

A real visitor to a web site. Web servers record the IP addresses of each visitor, and this is used to determine the number of real people who have visited a web site. If for example, someone visits twenty pages within a web site, the server will count only one unique visitor (because the page accesses are all associated with the same IP address) but twenty page accesses.


Universal Resource Locator. An address which can specify any Internet resource uniquely. The beginning of the address indicates the type of resource – e.g. https: for web pages, ftp: for file transfers, telnet: for computer login sessions or mailto: for e-mail addresses.

URL Submission

The process of submitting a webpage to search engines.

User Agent

Each time a web browser or other client connects to a web site, they report a USER_AGENT. Common user agents include Netscape, Opera, and Internet Explorer. In the context of Search Engine Robots or Spiders, a CGI program can read the USER AGENT and deliver custom content to that user or robot. The User Agent can also be included in a robots.txt file to allow or deny access to the web site.

Virtual Domain

A domain hosted by a virtual server account.

Virtual Server

An account on a hosting company server, usually linkedc to its own domain. This provides an inexpensive way to run a web site with its own top level domain, and is usually indistinguishable from having a separate physical server, except that the virtual server may share an IP address with other virtual servers on the same machine. A virtual server account is fine for most uses, but will often be slower to respond than a physically separate server, and physical access to the machine will seldom be allowed. The cost of a virtual server account is a small fraction of that needed to run a real server, mainly because of the expense of the dedicated line needed to connect the server continuously to the rest of the net.


Extensible Markup Language. A new language which promises more efficient data delivery over the web. XML does nothing itself – it must be implemented using 'parser' software.

XML Feeds

A form of paid inclusion where a search engine is "fed" information about pages via XML, rather than gathering that information through crawling actual pages. Marketers can pay to have their pages included in a spider based search index either annually per URL or on a CPC basis based on an XML document representing each page on the client site. New media types are being introduced into paid inclusion, including graphics, video, audio, and rich media.


Extensible Scripting Language – and XML style sheet language supported by the newer web browsers Internet Explorer 5 and Netscape 5.


Similar to a search engine, but with a database generated by hand. The URL is Yahoo! Charges an annual fee for each web site to be listed in their database.