Yes indeed, this is all true except the last phrase. You can quickly infer which demo the ad was made for my observing the location, time, or tv show.

Just look at the content surrounding the ads on daytime soaps, college ball, anime cartoons. Billboard next to (My apologies for this shorthand, I can't think of any polite way to make this next analogy) "Inner City" liquor store, suburban daycare, or just along the interstate.

As well as dead reckoning, I'll bet a local library has the spend on paper in some industry publication. Anyone in the industry can probably rattle off the spend and get pretty close. Plus, since they are marketing ad space for money, why not send over a proposal and see what the initial offer is?

Surely this takes more time than glancing at some Facebook reactjs ad timeline which is for sure not edited by an algorithm, but like I said there is a finite amount of billboards and tv channels. One grad student wouldn't do it, but however many you need for the internet is sure going to cost you.

Cable subs are going one direction, so it’s probably better to think about the other alternative mediums. These would be streaming services like Hulu, YouTube, Roku, digital billboards, and digital ad impressions through ad exchanges. All of these will offer significant ways to personalize and customize ads for viewers and have no audit system presently. I don’t see how Facebook removing political advertising remotely solves the problem going forward.