I just launched a very unique book-trading website. Ron mentioned it on Beatrice -- perhaps your readers would also be interested. It is an automated system that finds good homes for members’ used-books, while getting them titles they want in exchange.
Membership is free, and it's easy to use. Like Netflix (the famous DVD-by mail website) everything is automated, and postage is provided. But instead of getting DVDs from a warehouse, members get books of equal value from other members. They receive a much greater return on their trade-in than at used bookstores, and we are connected to the US postal service, so postage and mailer labels print from their own printers ($3.99 to receive a book, no charge to ship them).
Well, color me intrigued. I think I'd seen some stirrings about this on other sites but never followed through to the link. Jen and I have been talking about offloading some of our books anyway, and this might be a great way to do that. [Links: Bookins; Ron's comments]