AppFog is absolutely NOT being discontinued! We are incredibly proud of what we accomplished with PHP Fog, but we think that the AppFog is the true future of PaaS: polyglot and poly-infrastructure. We simply don't think that single-language PaaS on a single infrastructure is the future, and we're working on rolling all of the functionality from PHP Fog into AppFog, where you'll be able to deploy Node, Java, Python, Ruby, and other runtimes and deploy to a variety of infras.
AppFog is absolutely thriving right now and will be around for quite some time, we assure you.