> If that eats into your returns in a significant way, you don't have a viable business model A viable business model is one where, by definition, consumers wi

> If that eats into your returns in a significant way, you don't have a viable business model A viable business model is one where, by definition, consumers will purchase your thing at levels that are sustainable. People use apps more than they use web browsers for the most part. Tumblr has to build what people want.