Whether you've noticed or not - at the end of July - Google silently added a new feature to Google Business Listings returned in search results: 'typical time spent here'. If you haven't noticed it yet it could be due to the fact that currently this feature is only available on mobile search results, and is not displayed on results found through a desktop browser. See below for a screen shot of the same search result on both Safari for iOs and Firefox on a laptop:

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Search Result on Desktop
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Search Result on Mobile

The 'People typically Spend' information will show you either a specific time, like example above, or a time range, such as "30 min - 45 min". In our experimentation it does not seem to be displayed for all search results, but only popular locations such as chains and often visited shops. This is most likely due to the lack of data on the less-visited locations.

We are safe to assume this information is taken from Android's location services, and location history, which is opt-out; meaning that a stock Android phone is tracking everywhere you go, and how long you stay there. Not interested in that? LifeHacker has a good article on how to turn off and clear your history: http://lifehacker.com/psa-your-phone-logs-everywhere-you-go-heres-how-to-t-1486085759.

I would expect this feature to roll out for Desktop browsers sometime soon, but in the meantime - I wonder if knowing how long someone typically spends a location is valuable enough information for me to ask that myself, and strangers, allow a company to track and aggregate where and how I spend my time...