[wesd]

Google has been trying to tie store purchase to ad impression [1]:

"This location tracking ability has allowed Google to send reports to retailers telling them, for example, whether people who saw an ad for a lawn mower later visited or passed by a Home Depot. The location-tracking program has grown since it was first launched with only a handful of retailers. Home Depot, Express, Nissan, and Sephora have participated."

[1]https://www.washingtonpost.com/news/the-switch/wp/2017/05/23...