Taking things in a new direction, I started modulating pitch based on daily visits. (Well, technically, average hourly visits by day.) When I showed it to Gabe, his response was, “Are you talking to aliens or something?”
This one modulates the pitch based *changes* in visits per day. When you hear a blip of a high note, it means that day had a big jump in visits.
This one modulates the pitch based on the raw number of visits per day. This data spans a few years, so as the site gets more and more visitors over time, the pitch goes steadily up, with some seasonal regressions.
LOTS more to be done, but I am SO into the sound.