My take is that advertising may work globally, in that if any advertising occurs it may have an effect, but each player is a fringe in the advertising market an

My take is that advertising may work globally, in that if any advertising occurs it may have an effect, but each player is a fringe in the advertising market and may have their tide lifted simply by domain awareness of advertiser topics. Ad effectiveness for specific brands may be complete bunk. But advertising effectiveness for a product space may do well to raise awareness.