Could, cloud cloud, the cloud is HERE! I love articles like this http://alan.blog-city.com/has_amazon_ec2_become_over_subscribed.htm# Really interesting read, and makes a lot of sense. The problem is that you don't have visibility into what they are running and how well its running. Running my business on a completely unknown infrastructure would be a no no. I understand the internet is a big shared infrastructure, but wouldn't you rather know the specifics about the performance and capacity of your infrastructure.
This is an interesting thing to think about before you move apps all over the cloud, and have to manage a mess. I do like some of the monitoring which is being done by products like Zenoss : http://mediasrc.zenoss.com/documents/Using+Zenoss+to+Manage+Cloud.pdf . I like Zenoss a lot, but haven't done a full deployment of it yet. I might have the opportunity to do that soon!