Big step forward by Foursquare by changing from a "friends" model to allowing users to follow & have followers. (of their profile)
This is another move towards creating a new layer of influencers within Foursquare based on their activity levels including total number of check-ins, badges, Mayorships, etc.
Could be viewed as another step in the broader acceptance of individual influence score. (EX: Klout.)
Read more from the smart people at Hubspot below...