In reply to 王敏辉:
Hi Sammy, The best way to see who is in a particular group is to look at the member tab. Since it's a peer-to-peer community, the control of who is a member of which track is left entirely in the hands of the community member.
There is a scoring system built in, but unfortunately it's not very visible. You can see it with the number of stars when you hover over someone's name like this:
The scoring is based upon activities such as posting, friending, verified answers, etc.
I'm looking into ways to make it more visible so members can this with each post of fellow members.