The most precious commodity is user time

(…) Revenue follows user attention, not the other way around; unlike money, there is a finite amount of minutes in the day, and a finite amount of users. To put it another way, attention is a zero sum game

(via Instagram Direct, Twitter DMs, and the Social/Communications Map)

This certainly applies to all ad-based businesses, where volume is key! But there are other ways to build successful businesses though…