Speaking at #developconf on Wed
http://www.developconference.com/conference-programme/programming-social-features-with-no-money-

Server costs can kill a feature. Developers often need to develop online features and social functionality on a shoestring budget with no server support. Learn to build a player ghost small enough to fit in a leaderboard. Implement a player trading system with no server and breathe life into your world using big data. All with no hosting costs.