The site also acted as a key communication tool during , as well as when a U.S. Airways plane made an in New York's Hudson River.

"In terms of visibility and impact, Twitter has been very impressive," said Rob Enderle, an analyst with the Enderle Group. "It's been tied to revolutions and elections. And it's changed the way a relatively large number of people communicate... It's a new idea: communicating one to many."

Dan Olds, an analyst with The Gabriel Consulting Group, called Twitter's rise in the social media world "astounding."

"Tweets matter," Olds said. "For a deceptively simple and innocuous application, it's had quite an impact on the world. It has been an outlet for people rebelling against repressive regimes, and a channel politicians have used to communicate with their followers."

"Plus," he added, "it's a great mechanism that celebs can use to embarrass themselves. What's not to like?"