First of all Mike, I'm not sure I've ever met you, but this is a great idea and I'm happy to be aboard.
Second, I think of this as a place to discuss books, recommend books, trash books, etc. We could even get a little Oprah shit going on, giving our seal of approval to books. But I'm not sure about swapping books - the hassle it takes to send them long distances, despite the coolness of the idea, is offset by the ease at which we could get them at the library.
Third, I'm trying to get some of my friends to sign up. The more the merrier, I guess.
I just finished The Deptford Trilogy, recommended to me by Ben, and I'm currently on The Tipping Point, which I'll be done with in no time. Then it's on to The Great Influenza, which I've heard great things about. And it's not in my profile below, but the greatest book I've ever read is The Power Broker by Robert Caro. It probably helps that I'm a New Yorker for that, but it is what it is.