It was one of the Web's typical flash frenzies, a gaggle of geeks seeking the new, new thing. At 2 a.m. on Aug. 24, a new venture called Elastic Compute Cloud quietly launched in test mode. Its service: cheap, raw computing power that could be tapped on demand over the Internet just like electricity. In less than five hours, hundreds of programmers, hoping to use the service to power their MySpace and Google wannabes, snapped up all the test slots. One desperate latecomer instant-messaged a $10,...