A key question regarding the ongoing process of digitalization is whether it enables societies to overcome patterns of inequality or whether these patterns are fostered in the digital sphere. The article addresses this question for the case of online volunteering by examining the profiles of online and offline volunteers in terms of sociodemographics, resources, networks, and psychological engagement. We apply quantitative methods using a unique data set that provides comprehensive information on online volunteering. Our results suggest that two mechanisms are at work simultaneously: mobilization and reinforcement. The profile of “pure” online volunteers differs from the profile of “pure” offline volunteers (mobilization). Meanwhile, the hybrid type combining online and offline volunteering attracts individuals resembling offline (reinforcement) and online volunteers (mobilization). Thus, online volunteering seems to be both: a remedy for existing inequalities in volunteering and a way to reinforce existing patterns of social participation in increasingly digitized societies.