Hey guys, we've been working on Teledraw.com for the past 5 months, and when Doodle.no.de came out, we pushed hard to show you our take on the telephone drawing game as well. Let us know if you have any questions or feedback.
It's not entirely about spam, either... user accounts are closely tied in with the structure of the site, so it's hard to have accounts and anonymous users playing the same game. If you sign up, you'll see that there are a lot more features on the site than just playing! For example, the home page turns into a news feed sort of page, where you can see new activity on threads you've played in. The user profile page (here's mine: http://www.teledraw.com/user/camupod), which allows people to check out the turns you've played on previous threads.
Give it a chance, please? :)