Add definition of "Superzip" to Readme and somewhere at generated website (maybe under an "About" button).

[dukechem]

For example, the last line in Readme.md is currently:
Data compiled for Coming Apart: The State of White America, 1960–2010 by Charles Murray (Crown Forum, 2012). This app was inspired by the Washington Post's interactive feature [Washington: A world apart](http://www.washingtonpost.com/sf/local/2013/11/09/washington-a-world-apart/).

May I suggest appending another sentance, something like:

The Washington Post article from 2013 explains that

“Super Zips” is a term coined by American Enterprise Institute scholar and author Charles Murray to describe the most prosperous, highly educated demographic clusters [in USA] [by postal codes called "zip codes" in USA]. On average, they have a median household income of $120,000, and 7 in 10 adults have college degrees.