I think it's more enlightening to view it from the other side. If desktop and mobile advertising didn't have a material impact, why would profit-maximizing com

I think it's more enlightening to view it from the other side. If desktop and mobile advertising didn't have a material impact, why would profit-maximizing companies do it? If profit-maximizing companies are interested in this type of advertising, what is it about Facebook and Google that captures almost all their spend?