Not a good thing:

Rising income inequality has led to a growing number of Americans clustering in neighborhoods in which most residents are like them, either similarly affluent or similarly low-income, according to a new study detailing the increasing isolation of the richest and the poorest.

A report released Wednesday by the Pew Research Center said the percentage of upper-income households situated in affluent neighborhoods doubled between 1980 and 2010, rising to 18 percent. In the same time frame, the share of lower-income households located in mostly poorer neighborhoods rose from 23 percent to 28 percent. The percentage of neighborhoods that are predominantly middle class or home to a wider mix of income levels shrank.      WaPo

Most neighborhoods in America are still middle income or mixed, but the trend is disturbing.