What is the Deep Web?

To produce results, major search engines scour the Web. They follow links to index sites.
That's like dragging a net across the surface of the ocean.

These nets capture less than 1% of Web content. They totally miss the data behemoths.

Ask a database a question, and it generates a unique page.
These don't get surfaced to the indexable Web.

Also hidden are standalone pages and documents behind private networks, like academic journal articles.

The most hidden section of the Web is Tor. You can only get inside with special software that makes your location anonymous.