I don't think you can have a bubble in a commodity that cannot be traded. You can sell an app, but you can't trade it for more than you bought it for, because t

I don't think you can have a bubble in a commodity that cannot be traded. You can sell an app, but you can't trade it for more than you bought it for, because there is an infinite supply of copies of the app available for sale by the original vendor. The touchstone of a bubble is that even rational people, who know that (e.g.) there is no rational reason why a tulip bulb should be 1000x more expensive this year than last, nevertheless feel inclined to buy an expensive tulip bulb because tomorrow it will be even more irrationally expensive and they can sell it for a profit. The app situation is a mere boom. Which, as you say, is a garden-variety occurrence. Fields boom and bust all the time.