day-parting : A feature that allows a Web advertiser to specify when during the day their advertising is shown on search engine results pages.

deceptive redirection : A type of coded command that redirects a browser to a different location than what was expected via the Web link that the user clicked.

dedicated server : A Web server that is used exclusively by one Web site, and not shared with any other sites.

demographics : User data such as gender, age, and so on.

direct type-in traffic : Users who type a URL directly into their Web browser’s address bar.

directory : A list of Web sites a search engine can search through that’s typically compiled by people, rather than by computer programs.

distribution : The placement of a keyword throughout a Web page.

domain name : The base address of a Web site, such as “”

domain name registrar : A company accredited and authorized to register Internet domain names.

doorway page : A Web page submitted to search engine spiders that has been designed to satisfy the specific algorithms for various search engines, but is not intended to be viewed by visitors. A doorway page is usually filled with text content that makes it rank high for a certain keyword.

duplicate content : Identical or similar content that appears elsewhere on a Web site or on the Web.