1958- In response to the USSR's launch of Sputnik the US creates Advanced Research Project Agency (ARPA) within the Defense Department to establish that the US has the lead in Science and Technology.
1965- ARPA sponsors a study on "cooperative network of time-sharing computers"
1969- The first attempt in sending information resulted in system crashing after the letter G was entered in the word LOGIN. ( At UCLA)
1970- First publication of the ARPANET Host-Host protocol.
1971- Ray Tomlinson of BBN invents email program to send messages across a distributed network.
1972- Ray Tomlinson modifies email system for ARPANET, and becomes a big hit. The @ symbol becomes designated for the word "at". First computer to computer chat takes place at UCLA.
1980- ARPA net comes to complete halt due to an accidentally propagated status message virus.
1984- number of Hosts on the Internet breaks 1,000.
1989- number of Hosts on the Internet breaks 100,000.
1990- ARPANET ceases to exist.
1991- World Wide Web developed by Tim Berners-Lee is released.
1992- The number of Hosts on the Internet breaks 1,000,000. World Bank comes online. The term "Surfing the net" is coined.
1993- The White House and the UN come online.
1999- The Internet and The Millennium Problem.
2000- The Millennium wasn't a problem.
2007- According to Journalism.org 7 out of 10 adults are using the Internet as of 2005. And about 137 million adults reported using the Internet in 2005.
55% of Internet users have high speed access according to a story in Tech News World's website.

Sources: http://www.zakon.org/robert/internet/timeline/