I have been using Amazon AWS servers for years to host large videos and to store backup files in their S3 service. But apparently their servers have also become the home of a lot of spammers and bots. I have been in the process of locking down the security of my climate blog, testing changes that I will then migrate here (Incapsula front end, Disqus comments, a package of improved wordpress security changes, and ZB Block to catch what still makes it through. I am not naive enough to think that I am safe from hackers, but I can at least be safe from stupid, lazy, or automated ones.
Anyway, I probably don't see a lot of the bots any more because they hit either Disqus or Incapsula. But a great number still get through, and if they are persistent they get banned. What amazed me was that of the first 22 IP's banned, 9 were on the Amazon AWS servers.
My sense is that this is one of those classic tragedy of the commons issues, which happens when valuable resources are essentially free. I had an idea years ago, that I still like, that charging a tenth of a cent to pass each sent email would shut spam down. You and I might spend five cents a day, but spammers would be hit with a $10,000 charge to email their 10 million name lists, which would kill their margins. Don't know if there is a similar approach one could take for bots.