Adam Thierer links a sound post on the way concerns about privacy in the digital context seem inconsistent with our reactions in the physical realm:

Let’s say you are a tall, dashing, smartly dressed Chief Research Officer at a major Internet audience measurement company, and you walk into Nordstrom’s. A sales clerk you recognize comes up to you and says, “Hey, your wife’s birthday is coming up in a few weeks, and we just got in those sweaters she likes. Should I put a couple of them away for you in her size and color?” Now let me ask you. Does this hypothetical Chief Research Officer perceive this to be: (a) an egregious violation of his privacy, causing him to immediately rush home and write his state assemblyman; or (b) another example of Nordstrom’s world-class customer service? If you answered (b), then you’re tracking with me so far.

So how come if this exact same thing happens on the other side of the screen, it stops being outstanding customer service and turns into a violation of privacy?

Just to tack on a frivolous personal anecdote, I recall my father relating to me a visit to a Nordstrom’s we’d visited a year or two previous. The same sales associate who’d helped us then immediately walked up to him and said, without prompting: “Oh, Dr Sanchez! How is Julian enjoying NYU? Did he end up sticking with journalism? I hope that Joseph Abboud worked out for him. You were more partial to the Hickey Freeman’s, as I recall, though. I think we have a few in you might like.” When he’d finished picking his jaw up off the floor, he purchased several of the very aptly-chosen suits she’d recommended. Declan McCullagh wrote about the upsides of “zero privacy” for Reason a few years back.

All that said, I think there is a clear distinction between the knowledge stored in that Nordstrom’s associate’s impressive memory bank had and the kind of information compiled in  online transactions. As Lawrence Lessig and others have stressed, privacy is not just a function of what others know about you, but of the searchability of that information. That’s why we don’t fret a great deal that hundreds of dispersed people may each observe some fragment of our public comings and goings, but may get a little edgy when a network of closed circuit surveillance cameras can perfectly record and archive the same behavior, perhaps eventually subject to search by face-recognition technology that can pluck our trail from a vast store of tape. You may not care that the Rite Aid clerk knows you bought a tube of Astroglide; you may be less sanguine about having that data correlated with your dinner reservations later the same evening.