Facebook has released a new tool for its Open Graph that lets you tag other users inside Facebook-connected apps. Called Mention Tagging, once implemented by a developer the feature provides a bit more context when you post to Facebook from an app. So, for instance, if you mention a friend in a Foursquare check-in and then post the check-in to Facebook, the story on Facebook will link their name to their timeline and they'll receive a notification. This feature was actually already available in the latest version of Foursquare released last month, but now other developers have the option to include it in their apps as well. This news is just the latest move by the social network in its attempt to make more apps Facebook compatible — back in June an Open Graph update gave developers the option to build Like buttons into their apps.