Thought for the Google+, meta circle:Step 1:
Allow users to volunteer the names of their circles to an anonymous collective of circle names.Step 2:
Allow other users to select "Circle Suggestions" to give new connections an idea of how to place them into circles - or even do it automatically.
For instance: +Justin Riskin
asked people to Like a Facebook status so he would know who to put into a Settlers of Catan circle. Why not let users offer suggestions of how they, themselves should be classified...may be able to use Sparks as a primary indication?