This is an excellent point.
A big part of making the regional groups more active (and productive) is directly related to the leadership and participation within each group.
For instance, in the US-Midatlantic group:
There is regular activity. And so there is in the New England group:
These two were a recent spinoff of the former NE US Group (which may explain Lane, why you don't see much activity in that one).
Basically, we are seeking for volunteers to help lead regional groups, so that they become more than just online groups: so that we can turn them into the online resources for regional and local groups that meet regularly.
In your case, Cathy: Cara in TN has been pretty active in rallying Tennesseeans to meet up. She was the one that started the TN Diabetics group:
As for common interest groups, one that I am a member of that I keep on posting to and getting replies to is the Diabetic Geeks group. We see comparable level of activity with the Welcome Group...
Indeed, the only way to be current on activity within the group is to click on the "Follow" link, as you describe.
I would love to hear any more ideas on how to get Groups to being a more active area of the community.