URL shortening service Bit.ly says breach of customer data was likely caused by unauthorized access of offsite backup data maintained by a third-party hosting provider. The company says passwords in its user database may have been exposed, but that they were salted and hashed. Bitly also is accelerating its program to offer two-factor authentication to its users, as well as a program that would give users email confirmation of password changes. The compromise forced the company to invalidate all Twitter and Facebook credentials of its users and initiate a breach investigation.”]