One way to motivate users to be active and participate in Microsoft Q&A is to grant them badge and award for those who are actively answering and contributing to the community. Other than having internal badge here, it is possible to award special badge in Acclaim. Take a look at:
Badge in this website is well-known and well recognized and is very valuable.
I am wondering, it would be nice to add badge for active participations and moderator and whoever are actively contribute in this forum to motivate them.
The badge should also represent expertise in certain category too for over a period of time.