One and done: Factors affecting one-time contributors to ad-hoc online communities

Often, attention to "community" focuses on motivating core members or helping newcomers become regulars. However, much of the traffic to online communities comes from people who visit only briefly. We hypothesize that their personal characteristics, design elements of the site, and others' activity all affect the contributions these "one-timers" make. We present the results from an experiment asking Amazon Mechanical Turk ("AMT") workers to comment on the AMT participation agreement in a discussion forum. One-timers with stronger ties to other Turkers or feelings of trust for Amazon are more likely to leave more - but shorter and less relevant- comments, while those with higher self-efficacy leave longer and more relevant comments. The phrasing of prompts also matters; a general appeal for personally-reflective contributions leads to comments that are less relevant to community discussion topics. Finally, activity matters too; synchronous activity begets responses, while pre-existing content tends to suppress them. These findings suggest design moves that can help communities harness this "long tail" of contribution.