How would you describe the "tribes" in your corner of the jungle, and what are their tribal markings?

Tribes are everywhere. People pick some group to identify with, then adopt the outer markings of that group. Lately, whenever I see some young guy here in the Chicago jungle wearing a hat like this, there can be no doubt that he’s of the Hipster tribe.

Maybe your jungle is an office or a school or a factory or a suburb or a social website or some other institution. Each will have its own tribes; which are you seeing, and how can you spot them on sight.