Doodle Wall is a site I first heard about from Larry Ferlazzo, who has an excellent review of it
here. It's basically a site where you register an account that gives you a "wall" that you can draw on. I would compare it to
Art Pad in that respect just not as fancy.
After creating some drawings and testing it out I can honestly

say, I hope I never see this message again...
Doodle Wall gives you a wall that you can set to public/private which is nice (public lets others draw on your wall), but only allows you to draw on that wall once a day. I'm not sure why that is.
There are other features such as chat and so on. The jury is still out for me on this site but it does show promise.
For more info click
here.
BTW, I have an email into them regarding CIPA/COPPA compliance there doesn't seem to be any filtering, but they do require a user to be at least 13 yrs old w/ parent's approval, which is pretty standard.
Below is my poor attempt at drawing...