Google Rewards is an Android app that pays you to take surveys. Most of the payouts range from $0.05 all the way up to $1.00, just for taking simple surveys. But as the old adage goes, if you're not paying for the product, you are the product.
Here's how the story goes: I take my lunch break and walk to a local restaurant, on my way I change my mind and decide that I want Jimmy John's, so I change my path and walk to Jimmy John's, grab my Turkey Tom (no tomato) and then walk back to my office. A few minutes later I get a notification of a new survey available.
Google says this data is anonymized, which very well may be but in the end Google got the data it wants, another walking route to my local Jimmy John's.