(1) Clandestine websites that are hidden from the public. See dark Web and Silk Road.
(2) Content on the Web that is not found on a Google, Yahoo or Bing search because it has been coded to not be indexed by the search engines or is only available to users when they are on a site. The deep Web is thousands of times larger than the public Web (the "surface Web"). Also known as the "invisible Web," viewing such content is accomplished by going to a site and typing the query into a search box. Countless sites make their content available to anyone via one or more search boxes, and registration is sometimes required. Deep Web content is not directly coded into the Web pages. It typically resides within a database; however, there are search tools that can formulate queries to deep Web content. See LexiBot.
(3) Password-protected content on the Web available only to members and subscribers.
(4) See deep link.
