Facebook will have an event 4th of April, where they will present "their new home" on Android. A lot of web sites speculates that it will be the long rumored Facebook phone.
But I am sure that it's not a phone. Facebook has said that they never will release a phone because their is so many other that is doing that, so they will do the opposite.
So I am sure it's a launcher. A Facebook Launcher that replaces the default launcher.
Another rumor says that they will at the same time present a HTC phone with the launcher installed. To me that means that Facebook has a deal with HTC where they have remade Sense 5.0 to be a Facebook launcher that uses some of the Sense features. The launcher will have all the different Facebook apps and services implemented.
This Facebook launcher will hide all the Google services, so it will not be as easy to use anymore. So this Launcher will not be anything for me. I want to use Google servies and having the Google Experience. That's why I have replaced the TouchWiz launcher on my phone with the Nova Launcher 2. So I have the same experience as Vanilla Android.
I don't use Facebook much, and I don't like Facebook much, so I will probably not even try this launcher.