What is the Deep Web? A first trip into the abyss

The Deep Web (or Invisible web) is the set of information resources on the World Wide Web not reported by normal search engines.

According several researches the principal search engines index only a small portion of the overall web content, the remaining part is unknown to the majority of web users.
What do you think if you were told that under our feet, there is a world larger than ours and much more crowded? We will literally be shocked, and this is the reaction of those individual who can understand the existence of the Deep Web, a network of interconnected systems, are not indexed, having a size hundreds of times higher than the current web, around 500 times.
Very exhaustive is the definition provided by the founder of BrightPlanet, Mike Bergman, that compared searching on the Internet today to dragging a net across the surface of the ocean: a great deal may be caught in the net, but there is a wealth of information that is deep and therefore missed.
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