Users of Twitter post short messages that can be viewed either on a Web site or on mobile phones. They get to use up to
140 characters. It was launched publicly last summer, though started to take off mid-March after being adopted by technology bloggers attending last year's South by Southwest conference in Texas.
Sun Microsystems CEO Jonathan Schwartz last week singled out Twitter as the latest "viral" Web sensation with the potential to attract an online audience the size of a YouTube or Flickr. Schwartz said the Internet has "become so consumerized that social phenomena can take off like lightning." He believes Twitter should be taken seriously: "YouTube was funny, until it was worth $1.65 billion to someone," he said, referring to Google's purchase of the video company.