Yitzi chimes in with a cool link, which he calls the greatest site sign-up feature.. ever!
LibraryThing | Catalog your books online
If you go to this site, and you aren't yet a member, you type in a username and password into the login fields, and viola! you are now a member. Zero-step sign-up .. i likes. Why don't all sites work like this?? utterly brilliant.
Well, there are probably good reasons, like... ummmm... I'll get back to you ;-)