Key word: "their." The lynchpin or a lot of the surveillance efforts is accessing information that doesn't belong to the target of the surveillance. Phone call metadata is generated by the phone company, stored in the phone company's computers, and is used for the phone company's business purposes. Its the phone company's data, not yours. Same thing with the data Google and Facebook collect about where you go on the internet. You didn't generate it and you can't even access it. How can you say its "yours?" Its "about you" but that's totally different. If your neighbor keeps a diary tracking your comings and goings, you can't assert 4th amendment protection over that data.

Privacy advocates talk about "metadata is data" as if the government's lawyers don't understand that bits are just bits. What privacy advocates don't understand is that the "metadata" distinction is about generation, ownership, and control, which are implicated in the 4th amendment by the word "their."