Journey Into the Hidden Web: A Guide For New Researchers | Library & Information Science | Scoop.it

"1. What is the Deep Web? 

There are many words to describe the deep web, including the invisible web, hidden web, and even Deepnet.

The reason it exists is because the Internet has become so dependent upon search engines, and search engines are only as good as the web crawlers that serve up content for the results. Some researchers believe that the searchable web is barely 1% of what’s actually available on the World Wide Web..."