These are just random links and notes from my own research. Little or no experience is implied.

I use https://www.nearlyfreespeech.net/ for my very-low-traffic site since it's pay-for-what-you-use.

• Amazon (many say it's overpriced)
• Rackspace / OpenStack
• Digital Ocean
• Joyent

• dotCloud
  • Releases a bunch of open-source stuff; see e.g. http://blog.dotcloud.com/new-sandbox, http://blog.dotcloud.com/bootstrapping-the-open-source-sandbox-on-top-of-docker
    • Docker, "a runtime for Linux containers"
    • ZeroRPC
• OpenShift
• Heroku
• Google App Engine

• http://appsembler.com/blog/paas-bakeoff-comparing-stackato-openshift-dotcloud-and-heroku-for-django-hosting-and-deployment/
• http://redmonk.com/sogrady/2013/09/19/paas-questions/

• Docker (http://www.docker.io/) - "lightweight, portable, self-sufficient containers"
  • See also https://github.com/dotcloud/sandbox
  • http://blog.docker.io/2013/09/red-hat-and-docker-collaborate/
  • These open-source PaaS products build on top of Docker:
    • http://deis.io/
    • https://flynn.io/
  • Probably will work in the future with OpenShift
• OpenShift (PaaS)
• OpenStack (IaaS)
• Eucalyptus - Amazon AWS-compatible Auto Scaling, Elastic Load Balancing, and CloudWatch
• AppScale - Google App Engine-compatible PaaS; automatically adds and removes instances on AWS or Eucalyptus