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For example, if you have a smart lighting system at your house that you control with your phone, companies could know when you’re home and when you’re sleeping. If you fill your kitchen with smart devices, they will be able to know what you bought (via a smart refrigerator that helps you with your grocery list) and what you have eaten and how long you cooked it (via a smart microwave that chooses the perfect setting when you tell it what food you are warming up).