I would recommend allowing people to draw without signing up. Or at least provide a demo that people can use before signing up.<p>Why not have the drawing pad on the homepage? That way you won't lose people, like me, who could not be bothered to sign up because it involved filling in a form.<p>Maybe have a save button and when they click on that force them to save. That way they have an incentive to sign up because otherwise they will lose their painting.