Our group runs the mailing lists for a much larger organization. We are currently running in the neighborhood of 65 lists, with several having memberships numbering in the hundreds. In spite of that, our little workgroup of 8 has sent over twice as many messages as the second most active group. So where we may not use general mailing lists anymore, having migrated to social networks for our conversations, we still conduct a ton of conversations using our private little mailing list.