Facebook has launched their web version of the messenger. All you have to do is go to messenger.com (yeah, they’ve got that domain name) and sign in with your email or phone number. I find this a great way to get disconnected from Facebook itself and just use the messenger webpage.
I would love to have that included in Messages app so that I get all my messages in one place. On the other hand, in the past couple of weeks I’ve tested an unofficial messenger app for OS X.
It is simply called Messenger for Mac and it got to version 006 already. The app is pretty stable and it obviously works thanks to the new web version. The developers say this is not the official Facebook app, but a free and open-source project created by fans.