The whole ad industry and it's suppliers (Google, FB etc) are run by marketers. The fundamental theory that drives marketing is that the more you advertise, the better you sell (up to a point of marginal returns). No one has seriously looked at this approach to marketing in a long time. The result is that the billions spent on TV/Radio/Newspaper are moving to online advertising. While online advertising offers improved feedback, it basically is push advertising - shoving something in front of you in the hope that you will bite. Well, think for yourself, does that work for you? I, mostly, am supremely annoyed by push ads and I think the age of push ads will quickly die. In the future, marketers will have to engage more personally with buyers and require more humans to interact with buyers to form some sort of trust. The age of holding (and hiding behind) a big megaphone and blasting your message will quickly come to an end.