30/03/2000
Dr. Jill Ellsworth first coined the phrase to refer to information content that was "invisible" to standard search engines in 1994. In the year 2000, Michael K. Bergman coined the phrase "Deep Web" by saying:
"Searching on the internet today can be compared to dragging a net across the surface of the ocean. While a great deal may be caught in the net, there is still a wealth of information that is deep, and therefore, missed. The reason is simple: Most of the web's information is buried far down on dynamically generated sites, and standard search engines never find it."
Since then, the "Deep Web" was a more accurate term for what had been previously referred to the "Hidden Web" or the "Invisible Web".
Most of the web's information are buried deep inside websites and their servers. They can't be accessed by search engines, and they can't be "surfaced" so people can browse it as easy as finding things on the Surface Web.