[benologist]

If I have an EC2 server that is off most of the time the problem isn't that I have unused cpu cycles that could subsidize the cost a little bit, the value there is terrible and fiercely competitive - why you vs. spinning up a normal instance for an hour, or heroku, phpfog, appharbor etc, or every other hourly-billed provider.

What would be interesting is if you could turn the model around so people lease reserved instances off you without the upfront payment, I don't know how viable that is though.