Me on Facebook. I'll have more to say about libraries and Facebook in another post--just looked at the time!
OK, I'm not writing a new post, just editing this one and adding to it.
I have a friend who manages a a Facebook page for a university library. It seems like a library page on MySpace--that is, an institution trying very hard to be hip or cool.
But I do see the utility of creating events and inviting people to them. If the library page was more or less a plain one with events, hours, a gadget to search the catalog, and a bit more, I think it might work well. It would be easier, I think, for a university library, which can more easily ask people to "be friends".
I'm a bit of a Facebook addict. It's fun and the first good way I've found to actually get to know people (or get to know them better).