IBL - Abbreviation for In Bound Link. Any link on another page that point to the subject page. Also called a back link.

IBL - Abbreviation for In-Bound Link. A link residing on another site that points to your site.

ICANN - Abbreviation for Internet Corporation for Assigned Names and Numbers

ICQ - Form of abbreviation for I Seek You. Well known Instant Messenger.

ICRA - Abbreviation for Internet Content Rating Association. The Internet Content Rating Association (ICRA) is an international, non-profit organization of Internet leaders working to make the Internet safer for children, while respecting the rights of content providers.

IDF - Abbreviation for Inverse Document Frequency a measure of how rare a term is in a collection, calculated by total collection size divided by the number of documents containing the term. Very common terms "the", "and" etc. will have a very low IDF and are therefore often excluded from search results. These low IDF words are also known as "stop words".

IEP - Currency Code for Ireland Pounds

IIS - Abbreviation for Internet Information Services; web server software from Microsoft.

ILS - Currency Code for Israel New Shekels

IM - Abbreviation for Instant Messaging. As the name implies, this protocol allows for extremely fast communication over the Internet.

Internet - An interconnected system of networks that connects computers around the world via the TCP/IP protocol.

Image Map - An image that has different clickable areas linked to different pages. Image maps can either be imbedded in the HTML code or called as an external file. Search engines usually have difficulty crawling image maps when they are included from external files.

Impression - A single instance of online image advertisement being displayed.

Inbound Link - When site "1" links to site "2", site "1" has an outbound link and site "2" has an inbound link. An inbound link is an HTML or image link to a particular Web page from elsewhere, bringing traffic to that Web page. Inbound links are counted to produce a measure of the Web page or Web site popularity and Google’s PageRank based on number of Inbound Links. (see also: Backlinks)

Incentivized Traffic - The visitors who have received some form of compensation for visiting a site.

Index - The searchable catalog of documents created by search engine software. A term used to describe the database that holds all the web pages crawled by the search engine for each website. When used as a verb, it describes the process of converting a collection into a searchable database. With human-powered directories, the index contains the summaries of all web sites that have been categorized.

Index File - A file created by a search engine indexer program, designed to store information in a format that makes fast retrieval possible.

Indexability - Otherwise known as spiderability. Indexability refers to if a site can be indexed - or recorded - by a search engine spider. If a site is not indexable, or if a site has reduced indexability, positioning will suffer.

Information Architecture - The gathering, organizing, and presenting information to serve a purpose.

Information Extraction - A field of study related to information retrieval that attempts to identify semantic structures in order to extract relevant data.

Information Filtering - The same meaning as Information Extraction.

Information Retrieval - A field of study related to information extraction. Information retrieval is about developing systems to effectively index and search vast amounts of data.

Informational Query - A query about a topic where the user expects to be provided with information on the topic.

Infoseek - The old name for the Go.com search engine. Go.com was acquired by Disney and started displaying results from Overture, a PPC search engine. At the moment it displays results from Google.

INK - Abbreviation for Inktomi, the back-end search engine acquired by Yahoo. The Inktomi search engine is being phased out as Yahoo built a new search engine incorporating Inktomi's technology with elements of Yahoo's other search acquisitions.

InLinks - A synonym for inbound links

INR - Currency Code for India Rupees

Interactive Agency - An agency offering a mix of Web design and development, Internet advertising and marketing, or E-Business and E-Commerce consulting.

Internal Link - A link that points to another page within the same site. Most commonly used for navigation.

Internet - The Internet is actually a network of networks. It is a system of linked computer networks, international in scope, that facilitates data transfer and communication services, such as Telnet or remote login, FTP (file transfer protocol), email, newsgroups, and the World Wide Web.

Interstitials - A form of advertisement that is loads between two content pages. Also loads a commercial in the background of a Web page. When the user exits the page, he/her gets served a full-page, between-page advertisement in different media.

Intranet - Essentially a web site or group of web sites that is only accessible to people within a specific group or organization. Most large companies have intranets. Intranets offer a safe place for employees to publish information that improves workflow. Intranets typically house shared applications, internal telephone and e-mail directories, rules and regulations, help files etc. Many large intranets have a search facility that allows users to find specific information more easily.

Inverted File - A file that represents a collection of documents or database. The inverted file lists all words that appear in all documents in the database, as well as a reference to the document where the word appears.

Invisible Text - Text on a web page that is exactly or almost the same color as the background. The use of invisible text to load a page with keywords was once a popular SEO technique, but search engines can now detect invisible text and penalize sites that use it. Although there are examples of sites that use invisible text and "get away with it" on Google, the general consensus is that it is not worth the risk. The same results can usually be achieved by working the keywords into the visible body text.

Invisible Web - The portion of the Web not reachable by search engines therefore not indexed by search engines. A popular collective name for documents of types that search engines do not typically index. Because they are not in any search engine database, they can be very difficult to find and are in a sense invisible. Recently a couple of specialized search engines have begun an attempt to make the invisible web more accessible.

IP - Abbreviation for Internet Protocol. This protocol allows for machines to communicate to each other via the Internet. A numeric address that is given to servers and users connected to the Internet. For servers, it is translated into a domain name. IP provides the standard for the way data is scrambled and sent over the Internet, while TCP provides a standard for the way data is unscrambled. These two standards are essential to the working of the Internet.

IP Delivery - Similar to cloaking, a technique for automatically delivering different pages to different users based on the user's IP address. Although IP delivery has legitimate uses (like delivering different content to people from different geographical areas), it has been applied extensively in cloaking, causing IP based delivery to be banned by most search engines.

IP Spoofing - A controversial technique for reporting a false IP address. In the context of search engines, IP spoofing is sometimes used to refer to the practice of cloaking.

IPW - Abbreviation for Inverted Pyramid Writing

ISAPI - Abbreviation for Internet Server Application Program Interface

ISO - Abbreviation for International Standards Organization. (Correct Version: International Organization for Standardization)

ISP - Abbreviation for Internet Service Provider

IT - Abbreviation for Information Technology

IT - Language Code for Italian

ITL - Currency Code for Italy Lire

ITO - Abbreviation for Internet Traffic Optimizer a broader term for a person who optimizes not only for search engines but to get traffic from other sources such as blogs, RSS feeds and articles.

IW - Language Code for Hebrew

Ixquick - A metasearch engine located at www.ixquick.com

IYP - Abbreviation for Internet Yellow Pages