On the current internet, it's easy to create garbage that will last forever. The idea of having to pay to make something permanent is interesting to us, because it causes people to weigh the value of their actions.
Draw On This Website is straightforward: You hang out and draw with real people in real time. Drawings are ephemeral by default, and you pay 99 cents to buy colorful, permanent ink. You can see the mouse cursors of everyone who is hanging out and watching.