Okay so people who used to blog now prefer to post their observations on Facebook for the immediate interaction of it. I know what they mean now that I've been using Facebook for a few months. Hearing the likes and the comments is a kind of Pavlovian reward. It's true, I know the feeling.
But Facebook's search engine sucks, I hear. Nowhere near as good as Google's. So while you're getting more likes over there, you're not creating an archive, or a resource for others.
So that kind of settles it. If you're doing serious work, knowledge accumulation, relating to other people's work, the kind of stuff researchers, developers and academics do, Facebook is a dead-end. It's good for sharing pictures of the kids with grandma, but not for sharing your ideas to be referenced later. And you can share links to your stories on Facebook, just don't expect to be able to find them later, that way.
That's why Stack Exchange, for example, is on the web and not on Facebook. Without Google, there's no point accumulating knowledge. Wikipedia couldn't happen on Facebook.
For that, you still need the web and Google's search engine.