"Everyone has that one line they swear they'll never cross, the one thing they say they'll never do. Not something serious like I'll never kill anyone or I'll never invade Russia in the winter. Usually, it's something less earth-shattering."
These social networking sites all revolve around books. They allow you to create a virtual library of the books you've read or the books you own, rate them, connect with friends who also like to read, share booklists on particular topics, and more.