It’s probably not a new idea, but amidst its rising popularity, and increasing speculation that Twitter might charge “commercial” users, I wonder if charging business users on a per-follower basis might be one way the service could make money.

In the world of print, advertisers are charged on the basis of “impressions,” usually expressed in CPM (cost per thousand). It costs more to advertise in Wired than it does in Model Railroader. (No offense to model railroaders.)