The internet was invented under the guidance and impetus of DARPA's predecessor ARPA as a means of fast communication between research institutions and labs that were working on advanced research projects for the US military. This system was in use from the 70's to the 90's in relative obscurity, with the perception being that it was only useful for academics and researchers.
It was in use as a bulletin board communications system for many years prior to the point where Sir Tim Berners-Lee, working at CERN in Switzerland as a physicist in 1991, invented the method for linking web sites making it easy to browse through pages and research. He (and others, as he would readily point out) made the web easily linked and more useful as a tool to the layman. All of a sudden you did not have to be a computer geek to be able to use the internet.....all of a sudden you could "surf" the net.
Oh, and he gave it to the world for free. Did not have to, could have taken a miniscule percentage of all transactions on his system and been the richest man on earth (and I'm certain he saw this), but gave it away.
He's working on an even more advanced version of the web now at MIT, as the head of the World Wide Web Consortium.
[Edited 2005-11-17 15:35:23]