I wish the issue was explained a bit more in the article. In my opinion if the blocking was due to host-names then it had nothing to do with EC2. If the blocking was due to re-use of IP addresses then maybe it had something to do with EC2 (but the article didn't explicitly claim that). As far as I can tell the effect was due to using a outsider server at all (instead of carrying one into the client's own private data center), which I think has nothing to do with having used EC2.
You're right in that all hosting services suffer this problem to some degree, but it's a particular problem on EC2 since it's so easy to request IP for an instance that does something bad, then release back into the pool for other instances to use, a short time later.
It only costs a few dollars to that on EC2, whereas most other hosting services require at least a month's commitment and higher fee(s) before you can defile one of their IP addresses.
BTW, the reason I posted was to find out what other blacklists might be out there, so if your company is blocking access, I'd appreciate letting me know which service they're using.
You're right about the prior activity for the domain, but both Blue Coat and McAfee complained based on the IP address we're using now (i.e., the EC2 address).
But my purpose in posting this is to ask: what other filtering lists are out there?
Getting ourselves off is easy now, since we are a legitimate site; the hard part is figuring out who else may be blocking us.
