Developing skills through volunteerism and pro bono service

Volunteerism and pro bono service activities almost always involve volunteers exercising personal and professional skills, but which activities actually develop skills with quantifiable business value? The key is recognizing that skill development generates business value when it enables a person do his or her job better.  Specifically, this means gaining skills or experiences that help to complete job-related tasks more quickly, or produce more successful results (i.e., “productivity” in business jargon).