Facebook has released an update for Messenger, its stand-alone mobile messaging app, adding a few new features and making it available for BlackBerry users. The app now displays the online status of all friends, shows when the other person is typing, and makes it easier to add "top friends" to an ongoing thread. However, it'll be tough to catch the attention of ingrained BlackBerry Messenger addicts — especially since it still doesn't have read or delivery confirmations, one of the key features of BBM. 

On the other hand, Facebook Messenger has the potential to become a competitive messaging app, as it's now available for iOS, Android, and BlackBerry, rather than being tied to one ecosystem like BBM or iMessage. It also has a few advantages over other cross-platform clients, like WhatsApp, since little setup is needed — anybody with a Facebook account can sign in and immediately start using it — and all conversations are saved and can be viewed anywhere Facebook is accessed. Obviously, Facebook has the audience to make Messenger a success, but we'll have to see if it can take advantage of its user base.