Bob Lord writes on the blog:
"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."As a precautionary measure, owners of these accounts have been notified via email that their passwords have been reset.
If you are a Twitter user, check your email now.