Abstract: As social networks become more powerful and sophisticated, each member of a social network may belong to different communities. The computing reputation for users in a single community is not adequate anymore. As a result, a method of calculating global reputation for each member is desirable. Various considerations are described to address challenges related to global reputation for a user who participates in activities among multiple communities. Considerations on accessibility of a community, quality vs. quantity of submissions, posting ideas vs. comments, weighting of each community, and volatility of the reputation value are discussed in the present invention. Finally, a formula for calculating a global reputation value of the user is proposed by combining all the considerations. A system that implements the global reputation computation is described.