While I do remember Prodigy (First big internet thing), and how every add had 'AOL Keyword" and Rupert Murdock buying MySpace to promote his agenda, and thus killing it. I don't think a competitor to Facebook has really emerged yet.
I don't think most people realize how incredible useful Facebook is for people the run websites. It's not perfect, but it is a decent screening to keep trolls/spammers at bay. Look at how many sites allow you to log in with Facebook? It is a decent, and probably about the best way we have to authenticate that a person really is a person.
My buddy running a web site was getting so many spam comments, I think from China, that he couldn't delete them fast enough. Ended up having like 5,000 in a few days, and they were all just fake worthless junk that were killing his business. Updates, require people to long in with Facebook, problem solved. (Later adds fancy authenticator.)
As far as Microsoft, they are one the biggest research investors in the history of the world. They spent 10 Billion dollars last year just on research. I think they will be coming up with new stuff we can't even think of yet. I don't think it would be good for the world to lose that innovation.
And as far as the spying stuff, I think it is horrible. Microsoft involvement is bad. But I think it will come out that Google's is much worse as they admit when you sign up for Gmail they will be reading/scanning it. I think our privacy/protection laws will need to be adjusted and improved for the technology age we are entering.