[Blake_Emigro]

This is exactly how Google maps knows traffic conditions.

[seemslegit]

Is there an on-by-default "use my location data to push dubious pro-corporate agenda under the guise of academic research" checkbox in google maps ?

[Scoundreller]

And Google provides histograms of how busy a store is at each hour of the day.

Of course, the least busy hours are always my work hours.

[CriticalCathed]

It's not exactly the same. You're using a google product while they harvest your data, which is different than a company or researcher buying that data from a broker. Though I suppose Google could also be buying information separately.