Twitter has confirmed that approximately 250,000 users are affected in the recent hack but denied that the hack is related to the outage yesterday. As security measure, Twitter did reset all affected passwords and revoked all session tokens from affected accounts. The affected users will receive email from Twitter to notify them to create new passwords, so check your email. According to the official statement, Twitter observed "unusual access patterns that led to us identifying unauthorized access attempts to Twitter user data". Based on user reports, this recent hack seems to affect mainly users who signed up in 2007.
Ubergizmo , Twitter Hacked! 250,000 Accounts At Risk, Twitter Hacked! 250,000 Accounts At Risk