One way to understand motivation is by interviewing the volunteers. While this approach may elicit detailed information on the volunteers' motivation and actions, it is restricted to a subset of willing participants. For web-based projects we could instead use logs of volunteers' activities, which measures which volunteer did what and when for all volunteers in a project.
In this work we present some metrics that can be calculated from the logs, based on a model of interaction. We also comment on the applicability of those metrics, describe an ongoing work that may yield more precise logs and metrics and comment on issues for further research.