How is Popularity determined?
Popularity shows which areas have seen the biggest increase or decrease in number of devices, which areas are consistent and which are declining. It is a trend of growth, stability or decline in mobile device density within a Census Block Group over your selected time frame. Each census block group is ranked nationally, and the "change" is in the relative national ranking. One thing to note is that it is not a good measure of changes in population - instead, it is a measure of changes in activity.