Platform as a service (PaaS) AppFog has officially exited beta status and is now generally available. It supports Java, .NET, Node, Python, Ruby, PHP, MySQL, MongoDB, Postgres and other popular development languages and tools.
Two characteristics set AppFog apart from competing services. First, it offers a very simply pricing scheme that varies based on the amount of RAM users need. Up to 2GB RAM is available for free, with tiered pricing after that. Second, AppFog allows users to work with any public cloud infrastructure service they like, or they can choose to run AppFog on their own hardware. They claim it takes only 30 seconds to deploy AppFog on AWS, Rackspace, HP or Azure clouds.