How did they form? What are their specific traits? Stereotypes (even untrue, if marked as such)?
If cultural differences coincide with geography, please mention in, too.
In the questions about weird things people from different continents do somebody pointed out, that Europeans have little knowledge of this, so please fix my ignorance.
I don't know, and a quick search doesn't turn up anything. If they had moved over from Reddit I'd say it's a good question for AskHistorians.