Here are
my reactions to trying to work with facebook, heavily edited to remove the profanity. And google+ doesn't (or at least didn't) have anything in place to let you even try to post to it or fetch posts from it. If you can figure out how to make the api's from any of the big silos do something useful I would be happy to help integrate it into tiddlywiki.
Even twitter, which makes posting simple at least, has mostly indecipherable documentation on how to retrieve tweets using anything other than their embedded list things like I have on my site.
So in my experience it isn't so much as underdevelopment on the side of tiddlywiki as social networks refusing to play nicely with others.