Producers design commodities that appeal to users with different requirements. Producers decide whether or not a commodity includes a feature desired by some but not by all users. The cost of a feature can differ among producers. The cost depends on the features not on the number of users. Advertisers may pay producers of these commodities for the information about the users producers can supply them. This lowers the cost of a consensus commodity and its pice to users. Without the advertising revenue going to producers the commodity may not b produced at all.