Twitter?

I don't get it: what is the whole world loving about twitter? Yeah sure, I'm on there too. Until recently, I was even twittering publicly. But I decided to go private since I have unknown people following me and I simply don't like that idea and can't get used to it. Why would anybody who doesn't know me at all be interested in what I twitter? That's weird. So I threw out all unknown followers and went private. To come back to the beginning: what's the big deal about twitter? To me it seems like it's a sort facebook but reduced to status updates and public. But since I'm on facebook too it seems odd to update there and on twitter? And updating on FB and twitter differently is even more strange, why would I do that? The possibility of interaction with followers seems less attractive to me on twitter than on FB. Following a "discussion" with multiple comments seems easier to me on FB than on twitter. But maybe that's not the idea of twitter? So for me twitter at the moment is not attractive. I reduce my activity there. I stopped following most people since most of them didn't twitter anyway or very seldom and/or are (more) active on FB as well (so that's easy...hahaha).
If someone can explain the whole twitter idea to me, go ahead and tell me.