I like this--it's in particular a great demo of going from images to canvases and back again. Plus it's useful. Like he says, it's easily bypassed by viewing

I like this--it's in particular a great demo of going from images to canvases and back again. Plus it's useful. Like he says, it's easily bypassed by viewing source (or disabling JS), but it's still quite a useful thing for insecure applications, I'd think.