Twitter Security Alert! Some Problems Still Not Fixed!
Published August 26, 2009 | 
As recent as yesterday it has been made evident that Twitter still has some significant Security issues that haven’t been resolved to date, and everyone should be made aware of the possibility of security breaches with your account(s) if you make use of the Twitter application directly. So until these issues are addressed and satisfactorily resolved you should be sure to unfollow people you don’t trust, or use a 3rd party application, such as TweetDeck or Tweetlater for your Twitter needs, at least until the Security issues are resolved.
Mashable – Twitter Security Exploit Hasn’t Been Fixed Yet
TechCrunch – Massive Twitter Security Problem Not Resolved Just Yet