Adobe was breached recently which led to disclosure of over 100 million usernames and hashed passwords. While Adobe has been notifying its users about the breach and asking their users to initiate password change, Facebook has been working to provide security to its own users by cross-referencing the leaked database with its own users and notifying the affected FB users about password reuse.
Very often in the past, we have been observing that data breaches are increasing in magnitude vis-à-vis the data size. However, this news is a pleasant surprise as others are also mining the leaked data to secure their own users.
Hopefully, this trend is picked up by other social networking sites and various other organizations to notify and protect their users from any eventualities.