Netflix for books?

A friend recently said to me, "I wish there was a Netflix for books." My mind started whirring about the possibility of a business venture like this. Then I read this article in PW Weekly today.

Apparently some folks beat us to the punch. Booksfree has been around for seven years. Bookswim is the newcomer but has a similar model. I haven't had the chance to compare the two yet, so feel free to let me know what you think. Seems like a cool idea.