Mobile ad spending
Mobile ad spending is not lagging, it’s redefining the portion of economic activity that will be dedicated to advertising in the future. Advertising made sense when information was scarce and information sources were few. The value of extra sales generated by an ad today is a hell of a lot lower than it has been in the past, and the information-pervasiveness accorded by mobile computing is making it drop even further. One can compare prices, check reviews, see recommendations, and consult with friends on the fly. Who cares about what some ad says under such circumstances?