SkyFire, the iOS browser that landed in the iPhone stone yesterday, has already been pulled back from the App Store. Skyfire cited the reason because it was so popular that it was over powering their Flash-> H.264 video converting servers. They'll enable it after they add some capacity…perhaps there was more desire for Flash video than expected.
The browser hit #1 on the App Store's top grossing apps list within 5 hours of becoming available. The unexpected volume of downloads hammered SkyFire's server capacity and bandwidth, causing the developers to pull it from the store until they can build more capacity. Essentially, the app has sold out.