I've directly sampled a lot of mobile location data. The data is sparse. Most people do not have their location data distributed, and of those who do most have very few pings, and with Apple/Android now explicitly asking for location permissions the utility of the data which is available will decrease dramatically. Google, Apple, Verizon etc have significantly more due to their centrality in the technology but to my knowledge directly sell none of it. I understand the concern to for privacy but NYT makes the issue seem larger than it is.