I poked around a bit and saw that they offer a variety of "ownership" options. For $5 you can "own" the book for 30 days along with some printing and copying rights. You also have a 180 day ownership option for a higher price. For the same price as the paperback (on the few I looked more closely at) you can buy the entire book outright.
I think I like this idea. To me $5 is a reasonable amount to "rent" the book for a month. I pay almost that much to rent a movie from Blockbuster for one week. Obviously I'd check the library first, but given the types of books provided by UCP, I think this could have value.