[tslug]

If you had dinner at a restaurant, the restaurant knows, and if you used a credit card to pay for it, the payment processing company can figure it out by correlating the menu prices with the total bill. If you cooked dinner at home, you used groceries, and the supermarket has a record of what you bought there. If you googled a recipe, then google knows. If anyone intercepts your sewage and analyzes it, they will know, too. Your gas company knows how much energy you used on the burner. Your electric company saw the power spikes from your blender and microwave, and it saw your fridge compressor turn on. If anyone left Siri or Google Assistant or Amazon echo on during dinner, then they know. Anyone going through your trash can see what wrappers you threw out, or any leftover food.

What you had for dinner exactly is indeed "private" as you describe, but you see where I'm going with this? Your effective privacy is being pushed into a corner, because it's now possible with all of the little bits and pieces of clues you leave everywhere and the advent of big data to correlate these pieces into such a precise picture that your effective privacy is approaching zero over time.