BookCrossing

In case you haven't heard of BookCrossing, it's a fun program where members 'release books into the wild' and hear back from people who find them - sort of like dropping a bottle into an ocean with a message inside, or releasing a balloon with a letter attached - only this is organized, with a few safeguards (the finders send their messages to BookCrossing, not you) and it's all about letting other people know about your favorite books. Membership is free. Click the title link for more information.

BookCrossing was launched April 17, 2001. As of post time, it had 340,802 registered members, and 1,847,719 books registered.