This article examines the impact of cues to personal identity on the quality of dyadic collaboration via computer-mediated communication systems. Study 1 (N = 180) shows that an absence of cues to personal identity resulted in more work satisfaction and better subjective performance. Analyses suggested that this effect was mediated by perceptions of shared identity that emerged in cueless dyads. Study 2 (N = 91) confirmed and extended these effects, showing parallel effects on objective performance. The effects of Study 1 were replicated among high identifiers but not low identifiers. This provides direct evidence that social identity played a role in enhancing the quality of dyadic collaboration. It also illustrates the distinction between interpersonal and intragroup processes in online interaction. We conclude that when individuals in a dyad consider themselves part of an overarching social group, anonymity can improve collaboration performance as a function of shared social identity. © 2008 American Psychological Association.