AppleInsider | iPhone developer: App Store rewards "crap" apps:

At first, Sound Grenade was completely free.� Once it entered the Top 50, High said he decided to switch to an ad-supported model.� Now, after processing a million ad requests in 24 hours, the app is generating upwards of $200 per hour in clickthrough revenue.� In order to keep the app popular, he is looking into a few strategies.