Before I comment on how some interesting surveys by Pew Research intertwines with my own thinking on American Tribes, I thought I would bring this interesting stuff to everyone else's attention as well. You may consider this assigned reading if that helps motivate you to dig in, or supplemental if you're just auditing to be a Village Idiot someday.
It depends on how you slice up the pie, of course. Even if we can identify strong patterns of thought and attitude, no one thinks that there are sharp dividing lines between tribes. They can mate with each other and produce fertile young and all that. The folks at Pew identify 9 groups: Enterprisers, Social Conservatives, Pro-Government Conservatives, Upbeats, Disaffecteds, Liberals, Conservative Democrats, Disadvantaged Democrats, and Bystanders, each constituting 9-17% of the population. They have some nice statistical data to back up their theories.
This type of division tries to describe people's thinking as it is evidenced now, without regard to where it came from or where it's going. That is different from my tribal divisions, which tries to identify cultural continuities. Still, there's some interesting correlation.
A third method, also valid, would be to identify overlapping spheres of influence. National and regional media outlets, denominations, industries, and regional histories can be envisioned as broadcasters of different subcultures, with greater or lesser range and influence but not blocking other stations.