To Kill A Mockingbird

At one point Jem describes four kinds of "folks" in Maycomb County:"our kind of folks don't like the Cunninghams, the Cunninghams don't like the Ewells, and the Ewells hate and despise the colored folks." What does To Kill a Mockingbird teach us about how people cope with issues of race and class? Do you classify people in your world as different "folks?" Do you see those sort of distinctions today?