AppEngine social application
If you decide to use python, try a look to vikuit social. It runs over Google Appengine , it's open source ( GNU3) and perhaps it's a good base to your development.
I started developing my application in AppEngine Java, however I noticed that Facebook has officially discontinued the support for the Java API and the third party API was last updated a year ago.
Does anybody use Java + Social plugins? How has it been going so far? Should I switch to Python, I'd not want to since, I'm not very great with Python and have written significant amounts of code in Java already.