But as your experience shows, nobody can get far from Facebook.

I checked my smartphone after reading your post. It's an Android with the Facebook app built in, and by "built-in", I mean it's marked "system" and I cannot remove it. I've never logged in to Facebook through the app, yet it's running and has consumed 303 megabytes doing...nothing? It gets better--I'm fooling with it as I write-- If I can't remove it, I can at least trim it back...I cleared memory, but it's holding on to 249 megs. Jeez. I can't remove it, only uninstall updates. OK. Then I try to "Force Stop", but of course, it refuses to stop. Finally, there's a "Disable" button that seems new to Android. It seems to work--trustingly, judging by the fact that the legend changed to "Enabled"...but how do I know for sure if I can't remove the damn thing?

That Facebook app is scary. If I had logged in, the app would have been able to access my phone's contact list, which is synced by Google between all my Android devices. Any contact anywhere would have been sucked up by Facebook.

I can't get nearly as far away from Facebook as I'd like. I haven't even logged in to FB in years, but they're still aggressively intruding on my privacy.

But you're pretty sure they didn't get your contact list through your app. Could be you're just seeing "big data" at work--if you have a big enough data set, you can reveal anything, through patterns or through connections, or both. Facebook's whole existence is predicated on building "social networks" (that's actually a technical term, not just the title of a movie), and with a couple of billion registered users plus sensors installed on the majority of web sites, you can bet that Facebook is in the same league as the NSA when it comes to mining the take from a Niagra of surreptitiously-acquired data about billions of people.

So they simply put two and two together, and linked you with other people.

I see it all the time when they send me those chillingly-accurate suggestions about "friends", people I'm careful to ensure never meet in real life (c'mon, we all have people in our lives like that). I never told Facebook about those people, and I've checked, and in most cases they didn't either, but it doesn't matter. Facebook sniffs the internet, and it just knows.

The pressure to opt in is pervasive. As a Web designer, nowadays I'm being asked to set up login through Facebook or Twitter, because it saves a little money and there's some kind of cachet to the blue logos, as if you've joined an elite club. Bullshit, of course, it just means you've given them permission to set up sensor outposts on your web site, to track not only their registered users logging in, but anybody passing through. Of course it's free...to the web site owner. You and me pay the heavy price.

This is how a panopticon society is born, creeping tendrils of surveillance always sold as beneficial to us. Give up your privacy, and be safer, and a more efficient consumer, and a more pliable voter.

Seems like a fair trade, right?