I'm amazed and fascinated by LibraryThing.  I've only added a few titles but, already, it's fun to see how many other people have the same books as me.

http://www.librarything/profile/mpoupart

Because I love to search for information about the history of art and artists, I created a search engine for art history in Rollyo.

http://rollyo.com/mpoupart/art_history

Here is the link to my social search engine at Rollyo.com

http://rollyo.com/jessicallyson/

My search engine is called 'Cute Cats'. I would not recommend using it because it will suck all your free time away as you play kitten wars and look for ever-increasingly-cute cats. Something that should not have taken me very long ended up taking half a day because I kept looking at the cute kitty cat pictures. You have been warned.