@mvanpelt - There are a few ways to look into this, let's break it down:
Since the ultimate goal of a support community is focused on call deflection and how many dollars it saved you.
So, it becomes relatively important that who are the users (read superusers or super users in the making) who are elevating your community and allowing you to attain a level where your customers are getting the information they are looking for. In this case, the accepted solutions become really important closely followed by the number of kudos received. I'd even tie it down to the point where the number of important discussions was either converted into TKB (if that metric is available to fetch) or featured on the home page etc.
However, that is not the only thing which a support community must do. As with all the other things, customer satisfaction and the overall effectiveness of the community in providing the help customers need is still paramount. So, it becomes really important that who is contributing in terms of improving the product, means the ideas accepted from an individual and getting also if there is a way to get the sentiments of the community users. Here is an idea I posted, that might give you some more insights into other factors to look into.
I hope this helps.
