Many developers were unhappy with GREE's 2011 purchase of OpenFeint, a popular iOS and Android social platform that developers used to integrate leaderboards and friends lists and create custom challenges among players. After abruptly shutting down OpenFeint on Dec. 14, 2012, the company has released a replacement called OpenKit. The service is free, but the organization will determine a monthly fee if a mobile game reaches enough users that it needs to charge for providing a backend service. Can OpenKit replace OpenFeint for developers? Find out in this FierceDeveloper special report.