I finished something like this too, after working on it for about a year: http://papertogether.com/ http://papertogether.com/ Of course it's not as fully featur

I finished something like this too, after working on it for about a year: http://papertogether.com/ http://papertogether.com/ Of course it's not as fully featured, but it was a fun experience. I'm surprised to see that so many others had this idea and implemented it too - I thought I was the only one interested in collaborative drawing.