In a 2-minute ad spot, the company pitches its formula to fight obesity: Choose products with low or even zero-calorie content, including a broad array of low-calorie drinks from its own portfolio ( Coming Together).

FORBES: One Thing Missing From Coca Cola's Formula For Fighting Obesity

Mr Varian argues that this overcomes the free-rider problem, a particular pain for makers of online content because it can often be reproduced at zero cost.

ECONOMIST: Raising capital online