The radio industry doesn't like to serve up public information about its private business. This may account for the shroud of secrecy that has existed for nine months, only to be swept away when Dial Global fell by nearly 92 percent (over 1 year), with most of the drop occurring in one day. Dial Global blamed Rush Limbaugh.
Every time WABC contracts with a new advertiser and then puts their ad in the Rush Limbaugh Show, that advertiser is flooded with emails, tweets, phone calls, private messages, Facebook posts, letters, and maybe even faxes about Rush Limbaugh. The volunteers know that new sponsors are likely unaware of their own advertising schedule, so the messages will be friendly and (hopefully) helpful: "hi, I wonder if you are aware...?"
The database is so sophisticated, consumer-activists can report to a sponsor how many times their ad has been heard on the Limbaugh Show, and each date it has been run.
Limbaugh is a shit spewing sphincter and his audience are coprophagic cretins.