Pen-Elayne on the Web

Geometry Problem

Just added Zed and his MemeMachineGo site to the blogroll, largely on the strength of his link to this geometric chart listing different types of online activity. (Can someone please explain to me what the shape is called? I used to term it "concentric circles" but I know that isn't right, concentric circles are like what you see on a target. "Intersecting circles" and "convergent circles" don't sound quite right. I ask because it's very similar to the way I've always described the various subcultures in which I've been involved through the years, and how they often overlap.)