Twitter users are apparently at risk of having their accounts hacked if they frequent certain torrent sites. From what I can gather, the site owners have been sitting in wait, collecting users login information and then using these same username / password / e-mail address combos to attempt access to popular third party sights, Twitter included. According to Twitter Status "This information was then used to attempt to gain access to third party sites like Twitter. We haven’t identified all of the forums involved (nor is it likely that we’ll be able to, since we don’t have any connection with them), but as a general rule, if you’ve signed up for a torrent forum or torrent site built by a third party, you should probably change your password there."
The big message here is that you need to have unique passwords for the various sites that you frequent. I totally understand the desire to use a consistent user name, but at the very least you need to change your password!