This paper introduces the concept of "Social Thing" where things have unique personalities and autonomously build network to cooperate with each other as if they are living entities. In this context, each thing has its goal and different level of smartness. They autonomously cooperate to achieve their goals through inter-Thing communication. This paper proposes the concept of Social Things, with the emphasis on IoT application enabler for autonomous cooperation of networked things. In this paper, the system achieves autonomous cooperation of Social Things by providing them with preset conditional statements, combinations of triggers and action, which are triggered based on information transfer via interthing communication. On this system, Social Things shall autonomously exchange information about each other and take action by using this information to execute functions. The system has an advantage in which it enables the possibility to code cooperative functions of Social Things with comparative ease. The biggest contribution is achieving cooperation of mascots and a bench as case studies. They represent cooperation among private and public things. We will report implementation details and an experiment to discuss ways to design autonomous things.