This study examined how researchers participated in RIMSs and their motivations for participation. Profile maintenance, question-answering, and endorsement activities were used to define three cumulatively increasing levels of participation: Readers, Record Managers, and Community Members. Junior researchers were more engaged in RIMSs than were senior researchers. Postdocs had significantly higher odds of endorsing other researchers for skills than did full and associate professors, and they were more likely to be categorized as Community Members. Assistant professors showed a significantly higher propensity to be Record Managers than did any of the other seniority categories. Finally, researchers from the life sciences showed a significantly higher propensity to be Community Members than Readers and Record Managers when compared with researchers from Engineering and the Physical Sciences, respectively.