Other events singled out by New York's International Academy of Digital Arts and Sciences, which bestows the annual Webby Awards, were Iran's election protests, Craigslist's expansion and the launch of Google AdWords.
"The Internet is the story of the decade because it was the catalyst for change in not just every aspect of our everyday lives, but in everything from commerce and communication to politics and pop culture," said David-Michel Davies, executive director of the Webby Awards.
"The recurring theme among all of the milestones on our list is the Internet's capacity to circumvent old systems and put more power into the hands of ordinary people."
The Webby Awards list of the 10 most influential Internet moments of the decade:
* Craigslist online classified site expands outside San Francisco (2000)
* The launch of Google AdWords (2000)
* The launch of online encyclopedia Wikipedia (2001)
* The shutdown of file-sharing site Napster (2001)
* Google's initial public offering (2004)
* The online video revolution led by YouTube (2006)
* Facebook opens to non-college students and Twitter launches (2006)
* Apple's iPhone debuts (2007)
* The use of the Internet in the US presidential campaign (2008)
* The use of Twitter during the Iranian election protests (2009)
The 14th annual Webby Awards are to be announced in April 2010. They reward excellence on the Internet in a number of categories including news and other websites, interactive advertising and online film and video.