Ratings wars occur between broadcasting companies as they compete for the largest audience numbers, which are measured by BARB. Advertisers use these viewership numbers to determine which shows to advertise on in order to reach the biggest audience. Companies like ITV have moved timeslots for their shows like The X Factor in response to losing viewers to BBC shows like Strictly Come Dancing. New streaming services like Netflix and Amazon have also entered into ratings battles as they offer exclusive content to their subscribers.