A crucial aspect of everyday conversational interactions is ourability to establish and maintain common ground.Understanding the relevant mechanisms involved in suchsocial coordination remains an important challenge forcognitive science. While common ground is often discussedin very general terms, different contexts of interaction arelikely to afford different coordination mechanisms. In thispaper, we investigate the presence and relation of threemechanisms of social coordination – backchannels,interactive alignment and conversational repair – across freeand task-oriented conversations. We find significantdifferences: task-oriented conversations involve higherpresence of repair – restricted offers in particular – andbackchannel, as well as a reduced level of lexical andsyntactic alignment. We find that restricted repair isassociated with lexical alignment and open repair withbackchannels. Our findings highlight the need to explicitlyassess several mechanisms at once and to investigate diversesocial activities to understand their role and relations.