AC Nielsen Co. A pioneer of market research, Nielsen created the concept of market share in 1923. This occurred when his new company began checking food and drugstore shelves to tally product movement. His sales audits answered client questions about their marketing efforts, and as TV arrived Nielsen adapted his audit to deliver ‘the Nielsens’, those influential audience totals for programmes and commercials. AC Nielsen Co is his market research company, founded in 1923 in the US, that has become the market researcher of choice for the provision of consumer data on consumables, drugs, mass merchandise, and alcoholic beverages. AC Nielsen Co. became the world's largest consumer marketing research organization. It conducted retail and consumer audits and benchmarking services around the world. Nielsen's research continues to influence decisions related to campaigns, media schedules, sales promotion programmes, distribution patterns, entertainment, and event production. Many consumer products frequently use Nielsen data and packaging companies to determine which product lines would be the most successful for each location. It regularly publishes the Nielsen Index, which describes shopping patterns. The Dutch company VNU NV acquired AC Nielsen Co. in 2001.