Surface Web
Content on the World Wide Web that is available to the general public and is indexed by a search engine. Also called the "crawlable Web" and "public Web," links to the pages on the surface Web are displayed on search engine results pages. Descriptive text on the pages as well as metatags hidden within the Web pages identify the page's contents for the various search engines.
Deep Web, Invisible Web, Hidden Web
Content on the Web that is not found on a Google, Yahoo, or Bing search, because it can not be indexed by 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"). Password-protected content on the Web is available only to members and subscribers.
Dark Web
Any network that operates clandestinely and hides the identity of its users. Also called the "darknet."
