Following the mobile era, the technical architecture and the software development environment of mobile system plat form has been explained, and the future development direction has been summarized in the 5 ways. Closed operating system can be developed in the certain period. However, because of the lack of maintenance of the development infrastructure, it has been met its limit. Android, which is open source mobile, will be greatly spread, As it is the age SNS(Social Network System), I will introduce cases apply to formal community which used Twitter, Facebook, and so on.