[alibrarydweller]

I'm a fan of the podcast but one argument they cited seemed to have a pretty glaring error - they looked at the case where eBay was comparing incremental gain on search ads over no ads. It's methodologically hairy because eBay is a very major player with significant brand recognition.

"When Tadelis was working for eBay, the company was in the practice of buying brand-keyword ads. Which meant that if you did an online search for “eBay,” the top result — before all the organic-search results — was a paid ad for eBay."

This doesn't show that advertising doesn't work per se, it shows that eBay didn't hire a competent ad buyer. Whether or not you can prove the efficacy of advertising as a whole, this is not a valid approach.