There are many ways to estimate how similar two cities are — weather, demographics, taxes, etc. Jed Kolko from job site Indeed and Josh Katz for The Upshot used the distribution of job offerings. Just enter your city or a nearby metro, and you get something like this:
I punched in cities I’ve lived in or visited, and the results looked pretty good.
The analysis is based on job postings on Indeed, but I wonder if this would work with Census data. And can we apply this similarity index or some form of it to, say, individuals? Just think of the possibilities, Match.com.