Fig. 4

Each ad is mapped to the ‘maximum percentage’ from its region vector, indicating how regionally-concentrated it is. If the max percentage is close to 100, it means that almost all impressions came from one region, while if it’s close to 0, it means that many regions impressed upon the ad. a Histogram of max percentage per ad; inset: zoom-in on the last bin showing that most ads in this bin get 100% of their impressions from one region. b Histogram of the number of regions that impressed upon the ad. c Histogram of the amount of estimated dollars spent on an ad versus its max percentage value. d Histogram of the estimated number of users who were shown an ad versus its max percentage value