In addition to the excellent [answer by allquixotic][1], I'd recommend everyone considering cloud questions to vote on the [Practical Cloud Computing proposal at Area51][2]. I'm not behind it, but I'd very much like to see it succeed - we get a lot of those questions on ServerFault too, and most of them don't really fit there. I'd like to see them go to a good home.


  [1]: https://meta.superuser.com/a/11992/164830
  [2]: http://area51.stackexchange.com/proposals/96256/practical-cloud-computing