Fast-growing Twitter tormented by a worm

SAN FRANCISCO — An obnoxious computer program that barged into Twitter's mishmash of Internet chatter served as another reminder of the challenges facing the rapidly growing service.

The nettlesome program, known as a worm, targeted Twitter's network with four different attacks starting early Saturday and ending early Monday, according to Twitter co-founder Biz Stone.

The worm was set up to promote a Twitter knockoff, StalkDaily.com. It displayed unwanted messages on infected Twitter accounts, urging people to visit the Web site.

The worm was designed to automatically reproduce itself once its links were clicked on, but it didn't filch any personal information from the more than 6 million people with Twitter accounts, Stone wrote in a posting about the incident. Nearly 10,000 Twitter messages, known as "tweets," had to be deleted to contain the potential damage.

"We are still reviewing all the details, cleaning up and we remain alert," Stone reassured Twitter's audience.

Michael "Mikeyy" Mooney, who created StalkDaily, acknowledged unleashing the worm in a posting on his Web site.

He provided a link to a story on BreakingNewsOn.com that identified him as a 17-year-old from Brooklyn, N.Y. In that story, Mooney said he created the worm out of "boredom" and a desire to prove how easily Twitter could be infected with malicious coding.

In an e-mail exchange Monday, Mooney agreed to be interviewed by The Associated Press. But repeated attempts to reach him at a phone number that he provided were unsuccessful.

In his blog posting, Stone indicated that Twitter may take legal action against its tormentor. In a Monday e-mail sent to the AP, Stone said he didn't know whether Twitter will go after Mooney.

The trouble represents another rite of passage for San Francisco-based Twitter, which has emerged as a popular way to communicate on the Web and mobile phones since its debut three years ago.

Twitter's system, which limits messages to 140 characters, is used to broadcast both mundane and tantalizing information by a diverse group of users that include teenagers, celebrities, news agencies, politicians, police departments and companies.

Twitter's broadening reach makes it an inviting target for mischief makers and scam artists. Two of the Internet's biggest online hangouts, Facebook and MySpace, both have had to grapple with similar threats.

The widening usage also occasionally overwhelms the free service, whose 30 employees have been subsisting on about $55 million in venture capital until Stone and fellow co-founder Evan Williams come up with a way to generate revenue.

Although it doesn't break down as frequently as it did in its early days, Twitter periodically is inaccessible because its computer servers can't handle all the traffic.

Such challenges have spurred speculation that Twitter eventually will be sold to a larger Internet company. Twitter already spurned a $500 million buyout offer from Facebook. There also have been unsubstantiated reports that Internet search leader Google is eyeing a possible bid for Twitter.

Both Williams and Stone have said they intend to build Twitter into a profitable, independent company.