Do you want to know if a website is running on EC2? Use this tool to figure it out quickly.
For the domain www.rightscale.com, I found the following IP addresses:
174.129.230.90 - It's running on EC2! - PTR points to ec2-174-129-230-90.compute-1.amazonaws.com
174.129.238.229 - It's running on EC2! - PTR points to ec2-174-129-238-229.compute-1.amazonaws.com
Some EC2 sites: Some surprising sites that aren't running EC2:
- info.rightscale.com - apparently they only eat some of their own dogfood
- www.amazonaws.com