Got a lot of LEGO? I do, and it's incredibly hard to keep track of it. Brickset helps with that - the site lets you create an account, log in and register all of your sets. It has been operational for a long time and Huw has worked on it with dedication, and the result is the best source of set information on the 'net.
Swooshable borrows the official LEGO instruction list the site is hosting, adds some data from other sources (like Bricklink) and use that as a big chunk of the official LEGO instructions. In return we provide Brickset with a more complete list of instructions from other sources. We also keep track of what parts Brickset index in our parts directory.