Twitter says that torrent sites were used by hackers to crack the Twitter login credentials of multiple users. Here’s how:

Twitter discovered a number of compromised “torrent” sites that had been set up specifically to skim usernames and passwords. Scammers were then able to use the data to gain access to Twitter and other sites because many people use the same logon for multiple services.

The takeaway from this is that people are continuing to use the same email address and password (or a variant) on multiple sites. link.