This is quite a contentious topic, one of the best writeups is at http://www.circleid.com/posts/a_closer_look_at_the_controversy_over_the_internets_birthday_you

This is quite a contentious topic, one of the best writeups is at http://www.circleid.com/posts/a_closer_look_at_the_controversy_over_the_internets_birthday_you_decide http://www.circleid.com/posts/a_closer_look_at_the_controver... I argue/am on the side of the "Internet" coming into existence in 1983 as that's when ARPANET switched to TCP/IP and therefore represented anything like what the Internet is today. The Web is not the Internet, however.