Bernie Goldbach found a pertinent discussion on Reddit.
TOO MANY OF MY friends have gotten really bad at privacy. "You know what happened on 9/11" they tell me with bated breath.
They're accepting a massive deterioration in liberty because they cannot fathom what might happen. They're hopelessly uninformed because they've never worked with contaminated data sets. And they're unaffected by oversharing that so easily becomes a part of their socially networked lives.
Two generations from now, historians will marvel at how the first cohort of truly connected citizens stumbled through levels of protection that people need in order to keep their affairs to themselves. This isn't a matter of secrecy--it's all about privacy. Cory Doctorow explains, "Privacy isn't secrecy. I know what you do in the toilet, but that doesn't mean you don't want to close the door when you go in the stall."
I once got entangled in a fishing expedition that was commissioned to figure out if I'd done something wrong with travel vouchers. Because of an unrelated Post-It note, the investigation spun into a drug investigation and then soon involved counterintelligence because of my TOP SECRET clearance. The supervisors reading all the unvetted information formed totally different interpretations than the intelligence specialists who normally sanitise the data trawls. And that's what could happen to any citizen who reads your background through the prism of unconnected data around you.
In a short piece for the Guardian , Cory Doctorow points to Naked Citizens, "a short, free documentary, documents several horrifying cases of police being told by computers that someone might be up to something suspicious, and thereafter interpreting everything they learn about that suspect as evidence of wrongdoing.  For example, when a computer programmer named David Mery entered a tube station wearing a jacket in warm weather, an algorithm monitoring the CCTV brought him to the attention of a human operator as someone suspicious. When Mery let a train go by without boarding, the operator decided it was alarming behaviour. The police arrested him, searched him, asked him to explain every scrap of paper in his flat. A doodle consisting of random scribbles was characterised as a map of the tube station. Though he was never convicted of a crime, Mery is still on file as a potential terrorist eight years later, and can't get a visa to travel abroad. Once a computer ascribes suspiciousness to someone, everything else in that person's life becomes sinister and inexplicable."
Even if you've nothing to hide.
1. Cory Doctorow -- "The NSA's PRISM: Why You Should Care" on the Guardian Blog, June 14, 2013.
2. Journeyman Pictures -- Naked Citizens. NTS: We need to buy this for our creative multimedia programme.
3. Glenn Greenwald -- "Snowden's worst fear has not been realised – thankfully" in The Guardian, June 14, 2013.