Software maintenance is a highly collaborative activity whose social context is rarely addressed. To explore this context, we conducted an ethnographic study at a large technology company involving participant observation with software engineers. Thirty-six participants (nine managers and twenty-seven software engineers) at the company participated in semi-formal interviews, while six months of participant observation produced insights about the work practice. The paper presents nine key observations that demonstrate the social context of maintenance activities. These observations provide a description of how work was divided between groups, the social dependencies that exist between groups, challenges in managing branches, the role of small projects, issues of making cross-group changes to source code, how dependencies are identified, problems of confidence in testing, and the impacts of working across widely different time-zones. The paper also highlights implications these observ...