Okay, I knew I was missing something. Let's just say those numbers are just for the halfcourt set and they'll run whenever they get the chance.
4th? LA, NYC, and Chicago are definitely larger. Then SF bay area, Boston both sound larger than Houston, at least more fun. And if you use Chinese standard, Houston isn't big at all. Don't be upset.
Seriously, Houston *feels* like a ghost town compared to any major city in China. It's not that Houston's population's small, but rather it's really spread apart. You walk around on the street, taking buses or the subway to different places. Basically, no interaction with other people on the street in general.