The cloud buzz has reached a fever pitch. So who is actually using cloud computing, and for what?<p>To clarify, I'm talking about computation (EC2), not file stores (S3). Furthermore, I am excluding traditional VPS providers (Slicehost, Linode, etc -- don't get me wrong I love both of them). So cloud services would include, but not be limited to: EC2, AppEngine, Rackspace Cloud/Mosso, Heroku type of services.<p>So, are you using cloud services, and for what? Your whole infrastructure or just part of it? How big are you?<p>I'm also curious about auto-scaling. Of course auto-scaling sounds amazing, but when I think of the hard problems that need to be solved during the scaling process, most usually aren't solved by bolting on more hardware (virtual or not).<p>So who's really using auto-scaling? Does it work for you?