1969: On Sept. 2, two computers at UCLA exchange meaningless data in first test of Arpanet. Stanford, UC Santa Barbara and University of Utah join by year's end.
1972: Ray Tomlinson brings e-mail to the network.
1983: Domain name system is proposed. Suffixes such as ".com," ".gov" and ".edu" come a year later.
1990: Tim Berners-Lee creates the World Wide Web.
1994: Marc Andreessen and others develop the first commercial Web browser, Netscape.
1999: Napster popularizes music file-sharing. World Internet population surpasses 250 million.
2002: World Internet population surpasses 500 million.
2004: Mark Zuckerberg starts Facebook as a sophomore at Harvard.
2005: Launch of YouTube video-sharing site.
2006: World Internet population surpasses 1 billion.
2008: World Internet population surpasses 1.5 billion.
Source: Associated Press