Major recent developments in the U.S. food system include the increasing presence of nontraditional grocery retailers, such as supercenters and drugstores, and competitive responses by traditional grocers, such as supermarket chains. These developments have contributed to sharp increases in concentration in the grocery retail sector, changing conventional relationships among retailers, wholesalers, and manufacturers. In such a competitive domestic food market, food companies are attempting to differentiate themselves from the competition by reporting voluntary activities that demonstrate social responsibility and by more-tailored advertising campaigns and product offerings.