Diaspora still exists, is an active project, and has users. Its problem isn't getting developers and pod operators, it's that people use social networks because their friends are there, and unless your friends are tinfoil hats and hackers your friends are probably not using Diaspora. And I'm not sure your friends have any reason to trust J. Random Hacker more than Facebook. I do, because that's my community, but if all you know about it is Silicon Valley and Salon articles about "brogrammers" I could see not having much confidence.
Entirely too true. However, there was a time when Diaspora was the shining white hope of all these Facebook oppressed because it was magically going to give them a Facebooky place that wasn't Facebooky. Then Google did the same thing and nobody left. I think Facebook has finally figured out that their continued success depends on locking in their users. I think Messenger was their play. And I think it will work.
I dunno. Facebook stopped being cool when your mother started using it. I think having a Facebook account is going to be the expected thing for a long time, but that doesn't mean it will remain the center of anyone's Internet world. I still have AOL Instant Messenger and ICQ accounts because I have a few friends I talk to regularly who still do and having Pidgin set up to speak ICQ and AIM is easier than asking them all to join the 21st century. Doesn't change that ICQ would be dead if not for the porn industry and how AIM continues to exist is a complete mystery.