What you are looking at is Ann Arbor, of course, color coordinated based on household income. Rich blocks, Poor Blocks put together a google map of every city in America. The reddest areas mean the average households are pulling in less than ~$16,000 and the darkest blue areas are reaching incomes of over $94,000. When you click on the map you can see the median household incomes, etc. I don't think anything is too surprising about the Ann Arbor, but you can take the map to any city and examine away.