Incentives for participation can also include Gaming. For Competitive learners, this has strong appeal, so you need to also make sure that everyone is on an equal playing field in terms of having the ability to earn a virtual reward, e.g. a simple virtual 'button' or other prize icon reflecting the specific topic they are learning. I try to avoid leaderboards, unless I am teaching people to be more competitive. Then, having one makes sense. Otherwise, everyone should be able to make it to the top and have the opportunity to become the winner, at their own pace (or whatever level or by timing that is desired for the group).
