Collision Detection has an interesting post on how KFC is attempting to thwart people who fast forward through commercials by making a commercial that is tailored to skippers. The idea is that if they put a single frame in the commercial with, say a code to get something for free, then people will actually not only watch the advert but watch it frame by frame to find the embedded code.
Of course, this sort of overlooks the fact that only one person needs to do this, then post the code to their blog or discussion forum to save everyone else the trouble. Sounds a bit dubious to me. Time will tell.