Some of the great activities that would attract instant crowd would be cash prizes. As much as I personally do not support the idea of throwing away monetary incentives for the sake of doing so, I believe Apple has done a really good job this time. It answers to the objectives of them wanting to thank it’s consumers for their never-say-die support as well as to encourage downloads which in turn benefits the partnering companies. A live countdown ticker on the iTunes page also creates further excitement as people keep a constant lookout for it.
This promotion is available only to most who are 13 or older in a country where there is App Store. Brands must learn to incentivise their consumers at the right time. This builds brand loyalty by not cheapening the brand image.