Library Thing

LibraryThing is an online service to help people catalog their books easily. A free account allows you to catalog up to 200 books. A paid lifetime account allows you to catalog any number of books.

In addition to cataloging your own library, LibraryThing allows you to check out other people's libraries, tells you who has similar tastes, etc.

Tagging is one of the important feature I found in Library Thing. Tags are a simple way to categorize books according to how you think of them. Once you have a hundred books or so, you need some way to organize them. Library subject classifications, including that of the Library of Congress, are one solution. For most personal libraries, however, they aren't much use. "Tags," informal, personal markers used on blogs and sites like Flickr and Del.icio.us, provide a better model.

So, why you are waiting... start entering your books... let others know what u read.