thoughts about Facebook and @Mainebot 's article https://medium.com/tootsuite/replacing-the-pillars-of-the-internet-235836580a0e

I don't think Facebook is like the others. And the reason, stupidly and maddeningly, are Real Names.
Before FB, if my aunt wanted to message your uncle, she'd have to get his handle (number, e-mail...) somehow.
Now she types in a name and gets the right person, just like that.
Facebook solves discoverability, at least for existing IRL social networks. I'm not sure a distributed thing can do that.