In 1993, the source code for the World Wide Web was released into the public domain.
The directors of CERN (Conseil Européen pour la Recherche Nucleaire) made it freely available to anyone, without licensing fees. This is considered by some as the single most important moment in the history of the Internet. Some historians mark this as the birth of the Web.
Learn more at http://www.livinginternet.com/w/wi_lee.htm#cern