Platform as a service (OpenShift & Appfog) future
Having used both OpenShift and Appfog in the scope of various small projects, I like both of them. The services enables developers to quickly start developing apps without worrying about time consuming server configurations. They also promise to be able to scale your app which I tend to not agree :)
Both Appfog and Openshift offers you generous amount of RAM (1GB and 2GB) but they have some restrictions about amount of server storage which i think are reasonable. The free plan exceeds most of what shared hosting services offer and make it very easy for us to develop small websites/apps. The price however rose dramatically and becomes very expensive if our app becomes successful and needs more resources. The paid plans are a lot more expensive than a VPS plan provider like Linode. While you do not need to worry about server configuration stuff, there are certain limit on what you can install. In that respect, OpenShift allows more flexibility as you can install more tools/libraries that you need.
While I use Openshift more, I like a lot of things about Appfog:
1) Appfog offers you more memory (2GB compared to Openshift 1GB)
2) Appfog has a very friendly friendly admin interfaces where you can stop/start apps, download source code, configure domain names, add environment variables and especially clone , create instances of your app. Openshift Managent Console is very limited. It is much better to use the command line tools instead of the console in OpenShift.
3) Appfog allows you to pick your server location. As I am in Singapore, I prefer an Amazon instance in Asia which offers faster access/speed. Openshift Amazon instance is US based and takes twice as long to access.
Openshift also has some benefits over Appfog:
1) We can ssh in OpenShift. It is not possible in Appfog.
2) We can create more types of server app in OpenShift. It is even possible to install a DO-IT-Yourself server type if not supported e.g. Tomcat
3) Openshift community is a lot more active. In addtional, the documentation is much better than Appfog which needs a lot of improvement in this area.
In future, probably I will create lots of mini apps in both of these platforms. They can act as each other's backups :) I like them much more over other services like Windows Azure, Heroku which we either needs to pay or gives you limited resources in the free version.