Twitter sent out emails to users warning that "as a precautionary security measure the micro-blogging site has reset your Twitter account password, and revoked session tokens for these accounts, and inviting you to create a new one."
"If your account was one of them, you will have recently received (or will shortly) an email from us at the address associated with your Twitter account notifying you that you will need to create a new password. Your old password will not work when you try to log in to Twitter," the company adds.
According to Twitter the service this week, "detected unusual access patterns that led to 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."
In other relates news, Foursquare began to offer its users a new option to display their Twitter handle when someone tweets their check-in at your store.
"It's a small change to help you better reach out to and connect with people who love your business. So instead of a customer saying she's "at Butter Lane," her tweet will say she's "at @butterlane"," wrote foursquare.
"If you manage a single location on Foursquare and have already connected your Twitter account, this change will happen automatically starting today. If you manage multiple locations, still need to connect your Twitter account, or want to turn this feature on or off, head to http://foursquare.com/tools," the company added.