The concept is not new at all - Spot the Ball is a competition that ran in UK (and possible other) newspapers going back at least as far as the 70s. It was a cash prize competition and was pretty popular, though it's died out in recent years.
I wanted to bring it back to get people to interact a little more with a highlights photo gallery - it's a lot more fun that way. IMO, it's interesting because it's just the right level of infuriating.