The Great Paperback Swap

I'm participating in the Great Paperback Swap. You mail a paperback and get thirty six sent back to you! It's a kind of pyramid scheme, involving six friends and names on lists.

I just received my first paperback: Snow Falling on Cedars, by David Guterson. Sadly, I don't know who mailed it to me! It was mailed here in the UK.

Has anyone ever participated in the Great Paperback Swap before? If you did, how did it go?