This paper provides an economic analysis of marketing innovation. A dynamic duopoly model is developed to study two forms of marketing innovation: γ, which allows a firm to acquire consumer information effectively; and σ, which reduces consumer transaction costs. The incentives and effects of marketing innovation differ markedly from those of product or process innovations. Although γ benefits the innovating firm, it hurts some consumers; and, while σ benefits all consumers, it may or may not benefit the innovating firm. Increased competition intensity reduces the value of γ but increases the value of σ. The private incentive is too high for γ but too low for σ.