In my article, I was treating Top 40 as a >F<ormat -- because originally it had nothing to do with musical genres at all! When Top 40 was first introduced, the only thing that really mattered was what was selling the most, so you could get Sinatra and the Beatles on the same radio station. But the process was to play from a specific list, and time went into researching that list, etc... so I guess I considered the Top 40 genre altogether different from the Top 40 Format (or, I guess process works just as well) and I was focusing on the latter.

I think perhaps a followup article sorting all that stuff out would be helpful.