This week was a tough one for Twitter. Not only did they have an odd bug hack but it was well publicized after it hit Press Secretary Robert Gibbs...His Twitter account said, "My Twitter went haywire - absolutely no clue why it sent that message or even what it is...paging the tech guys."
On 9/21, Twitter users started seeing strange pop ups, pornography, and messages that were obviously spam.
The problem was actually within the Twitter code itself which left a hole open and cybercreeps used it to get in and spread malicious links. What was very sinister about this bug hack was you could get tricked without clicking a link, just hovering over it!
The good news is, if you use Twitter apps such as HootSuite or Tweetdeck, you were not impacted. This was confined to an older version of Twitter.
Source: The Christian Science Monitor, Twitter Hacked? Not really. Here's the scoop, Chris Gaylord, September 21, 2010