Facebook working with data company that tracks whether its users purchase advertised products . Datalogix has purchasing data from about 70m American households largely drawn from loyalty cards and programmes at more than 1,000 retailers , including grocers and drug stores . Datalogix matches purchasing data from companies with Facebook users , based on corresponding Facebook features . Privacy concerns raising Facebook .
Facebook working with data company that tracks whether its users purchase advertised products . Datalogix matches purchasing data from companies with Facebook users , based on corresponding Facebook features . Privacy concerns raising Facebook .