What if you were told that the majority of the World Wide Web was never seen or accessed by most computer users? Think of it like the surface of the ocean—seemingly endless, but compared to the depth and real volume of the ocean, the top is hardly a puddle.
The Deep Web, also known as Invisible Web, Hidden Web or Deepnet, is all of the Internet content that doesn’t get indexed by the major search engines, such as Yahoo, Google and Bing. If the web crawler can’t see/find/index the content, it is impossible for the browser to display that content on the SERP (search engine results page). Because the information is buried and layered on dynamically generated sites, standard and traditional crawlers can’t locate it.
How big is the Deep Web? In the early 2000s, it was estimated that the deep web was 4,000 to 5,000 times bigger than the indexed surface web. The number is assumed to be much larger now.
How do you access the deep web? With a specific search engine that would track hyperlinks through known protocol virtual port numbers. Basically, you need Tor or another Deep-Web specific browser.
What will I find there? Be careful, because of the anonymity and secrecy surrounding the Deep Web, a lot of criminals set up sites specifically for illegal activities. A famous website that was recently shut down was Silk Road, where you could buy heroin, humans and even hire a hitman. Law enforcement also targets child pornography on the Deep Web that has been known to be beyond prevalent.
For the really curious, Patrick O’Neill’s “How to Search the Deep Web” can be found here.