Frederic, you are correct that email is an issue. But you can fairly easily contract with a number of 3rd party email services that work quite nicely and are not all that expensive. I'm not sure why you think it's a pain to trace problems. You may want to pick a provider that has real support people that can actually help. If Amazon came out with an email service that would be "interesting". It seems pretty far away from cloud computing per se, but the good thing is that they do know who launched each instance and they have their CC, so they could do some reasonable enforcement I suppose.