Member contributions are the lifeblood of online communities (OC) and a critical factor in their success. To help managers foster contributions, this research investigates how the level of social features (i.e., the number of social features shown in the OC interface) shapes member contribution at divergent levels of involvement. A 2 × 2 factorial design experiment (presence vs absence of members' profiles and evaluations, respectively; N = 353) was performed in a realistic setting on actual members of a North American health-related community. Member contribution was gauged by the attitude toward contribution and the social value of contribution measured. The results show that, while the level of social features has a positive and linear effect for members with low involvement in the community's theme, the effect is nonlinear (U-Shaped) for the highly involved members. Therefore, to improve contribution of members with low involvement, a community's administrator should offer more social features. However, for members with high involvement, affording one social feature (an interface offering either members' profiles or their evaluations) should be avoided because it lessens contribution.