First, he picked certain keywords and colored the U.S. based on the frequency of the keyword (divided by congressional districts).
Then he took each state map, and replaced most of the city names with the most common word from the personal ads in that city. He also did this for some cities, down to the neighborhood level.
Amusing things I’ve found - Fort Worth is “Loving” while Dallas is “Symphony” Also, Salt Lake City is “Mormon” (which is obvious), but right below SLC is “Flaming” And in NYC, you can tell where the ethnic neighborhoods are.
His state/city interface doesn’t work worth anything, but you can look at the actual jpegs. On the left side, at the very bottom of the second box, you might be able to see the text. I can’t on IE, but I could on Firefox. However, I know where it is, so I click on the debris at the very bottom of the box.