But I'm under no obligation to limit my own utility so as to maximize the pool of people who are not on FB so that your digital footprint is proportionately more shallow, Jacques.
Suppose, in any case, that I persuaded my valued social circle (perhaps 10 intimates, 40 casual friends, 150 acquaintances) to move off FB to some other platform. This is unlikely as I'm not the only or most important reason reason they're on FB, but anyway: what would be different? OK, there would be less commercial exploitation of our information, but that doesn't seem like your primary concern. The NSA would, doubtless, still be vacuuming up our conversations just as the NSA vacuums up all the discussions we have here, and can easily cross reference our HN handles with our more detailed and specific identities on other platforms. I could posit a secure platform where everything was encrypted and all interpersonal communications metadata on said platform was cryptographically obscured, but then we'd have 200 going to the same site every day, presumably to communicate with each other in secret. That in itself would be of interest to intelligence gatherers, and how difficult would it be to social engineer oneself into a group of 200 people? Not very, and once inside one has most of the access one needs already because otherwise where is the utility?
I can't help feeling that you're arguing for a very highly highly elaborated version of security through obscurity. I prefer the security of knowing that if anything happens to me it will upset enough people to have negative ramifications for my antagonist. I find the conceit that we can have a situation where private actors enjoy all the benefits of instantaneous and frictionless communication but government actors are enjoined from participating even at the user level by virtue of the political authority they wield neither theoretically nor practically sensible.