Wired has a good article about the recent Twitter hack.

 

"President-Elect Barack Obama was among the most popular requests from Digital Gangster denizens, with around 20 members asking for access to the election campaign account. After resetting the password for the account, he gave the credentials to five people.

 

He also filled requests for access to Britney Spears' account, as well as the official feeds for Facebook, CBS News, Fox News and the accounts of CNN correspondent Rick Sanchez and Digg founder Kevin Rose.  Other targets included additional news outlets and other celebrities. Fox won the hacker popularity contest, beating out even Obama and Spears. According to Twitter, 33 high-profile accounts were compromised in all.

...

Someone used the Obama account to send out a message urging supporters to click on a link to take a survey about the president-elect, and be eligible to win $500 in gasoline. A fake message sent to followers of the Fox News Twitter feed announced that Fox host Bill O'Reilly "is gay," while a message from Britney Spears' feed made lewd comments about the singer. "