reports that Columbia Heights is the 19th busiest station in the 86 station system. Often fairly crowded during morning rush hour, it's pretty busy on the weekends too with shoppers and diners, plus bar goers at night.
This is a big step of course, thanks to all the development in the neighborhood: last year Metro reported that Columbia Heights had the biggest ridership. I remember about 5 years ago when I lived in Adams Morgan, I'd use the Columbia Heights Metro sometimes and it was always empty, maybe a couple people there. Big changes.