These sorts of techniques have widespread applicability. Who needs facial recognition when you have kinematic behavioral analysis? Just imagine the trove of data you could pull from existing information sources if you had unlimited analytical time and computational power? As computing power becomes even cheaper and various analytical techniques become better our "effective privacy" window in our partially-anonymous society will grow ever smaller.
That's why I'm still entertaining the thought that we may be a "privacy vs. progress of mankind, chose one" type of situation. "These sorts of techniques" are the first scraches on the Great Web of Causality. I don't see a way to prevent it short of banning general-purpose computation. But are we going to deny ourselves all the advances in medicine, disaster relief, energy efficiency, etc. to protect ourselves from some future governments that may get funny in their heads? Maybe it's time to embrace that our "effective privacy" was only a temporary state of affairs, a historical abberation of the industrial age. I don't know if this is a good idea or not, but I suspect we'll learn to live with it and proper social customs will develop around snooping on your neighbours.
By the way, it's funny how often the discussions turn into "we need to stop technology X because evil advertisers will use it to do their evil things". It's not technology X that is the problem, it's evil advertisers that are assholes, and we need to find the way to get rid of the latter, not the former.
At this point we have to drag out the heavy philosophical tools and ask: what do we mean by progress? The "Whig view of history" is one of incremental improvement towards better states, but it's reasonable to ask what we mean by "better" and how the progress itself affects our view on what is better.
We also need to bear in mind that it's not just future governments but present governments in various parts of the world that will weaponise technology for control purposes. Behavioural analysis as part of the Great Firewall of China?
I think that the final destination here is going to be a near-complete lack of privacy in human relationships. Everybody is going to be able to look up everyone else's porn habits. Everyone one is going to know who does drugs, and who's cheating on who.
And as a society I think we're going to need coping strategies. Trying to protect privacy is only going to delay the eventual meltdown of privacy in our lives.
I think we are making good strides already though. There is less stigma around porn, around homosexuality, around fetishes. Religious tolerance also seems to be increasing. There are still problem points, but I think the trends are in the right direction. I'm happy to be proven wrong on this point though.
