I love this idea. The DrawTop is a sticker that goes on top of your laptop and basically turns it into a whiteboard surface. The one, ahem, drawback that I can see is you might pretty easily wipe off any designs you happen to have on it just by sliding your laptop into the usual protective case or holder, so the company's suggestion to use it as a makeshift notebook or reminder board probably won't work all that well.
Nevertheless, I can still see some good uses for this, like putting information on the back of your laptop at a conference or convention, or using it as a quick and portable collaborative sketch surface. The DrawTop itself is $10 for one or $14 for two, and it even comes with markers and stick-on accessories. Sure, you'll be covering up that Apple logo, but that's a small price to pay for a more useful laptop surface, no?