Twitter (and some other high profile sites) became the recent target of hackers who managed to access the usernames and passwords of around 250k accounts – underscoring the wisdom of having separate passwords for each of your online accounts: http://www.wired.com/threatlevel/2013/02/twitter-hacked/
“As you may have read, there’s been a recent uptick in large-scale security attacks aimed at U.S. technology and media companies. Within the last two weeks, the New York Times and Wall Street Journal have chronicled breaches of their systems, and Apple and Mozilla have turned off Java by default in their browsers.
This week, we detected unusual access patterns that led to us identifying unauthorized access attempts to Twitter user data. We discovered one live attack and were able to shut it down in process moments later. However, our investigation has thus far indicated that the attackers may have had access to limited user information – usernames, email addresses, session tokens and encrypted/salted versions of passwords – for approximately 250,000 users…”