There are so many different possibilities. I could see where Moffat brings Tennant back for a few episodes until the twelfth Doctor is found. Problem is that Tennant probably wants to shed the Doctor persona.
An interesting choice would be the actor who played in “The Next Doctor”. I thought that was an excellent episode and the interaction between Tennant and the “Next Doctor” was classic.
Facebook is what it is. I like keeping up with friends, with whom it would be difficult to do without Facebook.
It allows me to expand my likes and interests throughout the world. I don’t “Like” corporate businesses. My Facebook reflects me. I tire of all the political rhetoric I see (I live in a conservative state – so it’s Anti-Obama this and that) but just like television I can turn it off.
Facebook isn’t for everyone. Generally I like it. It’s not the greatest thing since sliced bread but it serves a purpose.