Guy from Elephant Disk is here, they're one of EC2+S3's biggest users. They only use it for non-real time stuff right now. He's terrified of stories about companies that use EC2 as their only web servers.

Issues

• EC2 instances have no persistent storage - need to code your own persistence solution.
• No static IPs - need some sort of dynamic DNS client.
• What happens if Amazon pulls the plug or changes something crucial? No SLA.
  • AWS is actually showing up in Amazon's financials. Helps assuage fears of it disappearing.

Companies built on EC2

• RenderRocket
• The AWS forums have lots of good examples and feedback
• Many more companies using just S3

Some companies have started to wrap services around AWS (e.g. RightScale) - check the partners page of AWS.

But: if you have something that parallelizes well, need scalability on demand, and can deal with the constraints, AWS is the shit. "AWS is the perfect startup environment; my credit card loves AWS."