It's not in itself a VPS no, it's an "application environment", that's self contained and runs inside the Linux operating system. You can have multiple applications running over multiple instances, and Appfog handle all the deployment, scaling, and back-end management.

Those Linux instances are hosted on one of multiple providers (your choice), for example Amazon, Rackspace, HP Cloud, etc.

I didn't ask if it was in itself a VPS. You know what I asked.

Thank you for giving me a little bit of an idea.

So basically, AppFrog launches VPSs with their own images on Rackspace or AWS for you, which you don't access directly. So back to my question.

Is there a button I can press to say that I want another 'instance' (= VPS)? If I press that button twice, can I get two 2GB instances? Or is there no way to ask for another instance directly, instead I deploy another app, and it will always just resize the instance up to 32GB at which point then it would finally deploy a new VPS?

I understand that hand-waving and magic is the way that you sell a 'cloud service'. I need more details about the mechanics of using it and also specific information about the implementation in order to evaluate it, however.

I mean not to be a dick, I think the idea of starting with 2GB of RAM for free is freaking amazing and the right direction to go.

Yeah you can explicity launch multiple instances at your own control, each one uses the same amount of memory - so you could launch 10 instances with 200MB of RAM, or 1 instance with 2GB of RAM.

It's definitely worth signing up for, I've been using it for a couple of months and overall I've been impressed, though they still have too many glitches for me to be entirely happy deploying an important application to it.

AppFog is a PaaS built on various IaaS virtualization platforms (AWS, Rackspace, Azure, etc.), not a VPS.

I'm sure all cloud hosts are built on virtualization...

Just think of cloud hosting as the next generation of VPS hosting.