I recently finished a great book. The kind where even after it's over you wish you could read the continuing adventures of the characters. Alas, there is and never will be a sequel to the book I just read. Which is why librarything.com caught my eye.

Library Thing works similar to del.icio.us, or other sites where users can take and recommend resources, but for books. So you can type in the name or author of a book, and it shows you how many other users of the site have that book in their collection. But it doesn't stop there, it also shows you what other books people have on their shelves "next" to the original book, so you can find people with "eerily similar interests". Because it uses tags, it makes it very easy to find other books of the same topic. And, because it has a rating system built-in to it, you can get suggestions on further readings that come directly from people who have read the same.