Definition of Deep Web
What does the term "deep web" mean? What is the definition of the "deep web"?
The "deep web" (aka "deep net", aka "the Hidden web") refers to the web sites that are not accessible via search engines (Google, Bing, etc).
There are certain measures that a webmaster can take in order to ensure that their sites are not indexable by the search engines - in many cases (but not all), webmasters make their sites inaccessible to search engines for a reason.
Sites in the "deep web" can include web sites that are readily accessible if accessed directly but not indexed by search engines, web sites that are password protected and web sites that are only accessible via an anonymity network, such as the Tor network.
For instance - the site "Silk Road", which was a marketplace for drugs and other illegal items, was only accessible via the Tor network. The Tor network, according to their site, is a "network of virtual tunnels that allows people and groups to improve their privacy and security on the Internet."
As mentioned, there are some sites out there that are part of the "deep web" for innocuous reasons. However, a large percentage of the "deep web" is inaccessible to search engines for a reason - they are hiding some sort of illicit activity.
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