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.
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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.