I've been thinking about your question for a day, and I'm really not sure. To me, this sort of thing is obvious. It's just how I think about Facebook. But some people are continually surprised at what Facebook knows about them, or what it can find out. And I don't know how to be more explicit with them.

In other words, I think that this sort of thing is implicit in using Facebook. But for some people, they're not. So do you remind them about this every time they do anything new? I don't know.