This paper constructs a tractable general equilibrium model for investigating the dissimilar effects of addiction and saturation on consumption and public policy. By introducing an industry‐specific intertemporal consumption externality, we provide clear analytical results that a lump‐sum subsidy for firms can increase welfare in the presence of a negative externality (saturation). A tax can accomplish the same given a positive externality (addiction). Unlike existing studies of cultural goods, these results are not based on assumptions concerning exogenous different preferences across groups, but rather on conventional monopolistic competition and consumption habit formation models in macroeconomics.