This (“Google has most of my email because it has all of yours”) is something I’ve wondered about before. It started like this…
I use LinkedIn probably as much as anybody else, but something I never do is allow a social media site to access my email accounts anywhere.
One afternoon, LinkedIn suggested that I link with my landlord. At first I was puzzled (“omg LinkedIn is omniscient like Google?“) then I realised what had happened; a couple of days earlier, my landlord emailed me and my flatmate. I didn’t reply, but it didn’t matter; LinkedIn trawled either my landlord’s email folders or my flatmate’s email folders, found the email and concluded that I might know everyone who sent/received that email. Plus I was connected with my flatmate on LinkedIn.
Now, imagine a scenario where the CEO of Boko Haram accidentally emails me instead of a henchman with a similar email address. LinkedIn and everyone else starts recommending that I connect with him because I must know him.
And PRISM makes the same conclusion.
Metadata is harmless, right?