To say that Facebook has a lot of information about its users is a bit of an understatement. The social giant knows about countless birthdays, relationships, jobs and vacations. And now, it's added your workout habits to the list. 

Facebook just acquired a Finnish startup called ProtoGeo Oy for an undisclosed sum. The Helsinki-based company is two years old and is the creator a popular a fitness app called Moves. The app launched last year has been downloaded 4 million times. 

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Moves is described as "an activity diary of your life," that records your daily exercise and burned calories. Though available for both Apple and Android phones, there are some features like a calorie counter which are currently only on the iPhone. 

The app positions itself as a simple and intuitive alternative to fitness tracking devices like the Fitbit and Nike's FuelBand. 

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With that in mind, it seems that Facebook is choosing an interesting time to get into the fitness game. Fitbit recently recalled its $130 Fitbit Force wristband after finding that it caused rashes in some users. Meanwhile, there have also been reports that Nike is moving away from wearables and shifting its focus to apps.

Like Instagram, WhatsApp and Branch before it, Moves will continue to be a standalone app, but the team behind it will be joining Facebook to "work on building and improving their products and services with a shared mission of supporting simple, efficient tools for more than a billion people."

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