What is CiteULike?
CiteULike is a free service to help you to store, organise and share the scholarly papers you are reading. When you see a paper on the web that interests you, you can click one button and have it added to your personal library. CiteULike automatically extracts the citation details, so there's no need to type them in yourself. It all works from within your web browser so there's no need to install any software. Because your library is stored on the server, you can access it from any computer with an Internet connection.
Why is it "social"?
You can share your library with others, and find out who is reading the same papers as you. In turn, this can help you discover literature which is relevant to your field but you may not have known about. The more people who use CiteULike, and the more they use it, the better it becomes as a resource. You can help with this process just by using CiteULike and through the invite a friend feature.
Check out InspireNet's CiteULike Library: http://www.citeulike.org/user/inspirenet