Much is being written around the thread of conversation that David Weinberger started and I responded to. I resolved long ago never to speak publicly about "privacy," as the conversation seems to immediately dive into a black-hole of nothingness. However, at the risk of falling into the same hole around "anonymity," I will try to say something intelligent about this subject. Please note, I've tried this in the past (the date on that article is 2002), but here I am trying again.
One of David's assertions was that "anonymity" was the "default" in the "real-world." I'm putting all of those terms in quotes because I'm already seeing debate about exactly what those terms mean. Setting that aside, let me say that I largely disagree with David on this.
David's reasoning behind the assertion says that people in a "big city" can't demand an identity from each other. While this is true, I'd argue that anonymity still does not exist. In order to explain, allow me to (simplistically) break all "real-world" interactions into two broad categories: social and transactional. Social interactions do not involve the exchange of any currency. Transactional interactions directly involve currency exchanged for goods or services.
In the transactional realm, the default is *not* anonymity. Even in the case of cash (which is a government institution *proxy* for identity), anonymity is not the default. Every transaction in the real-world involves not only explicit identification (ATM cards, credit cards, driver's licenses, or the proxy of cash), but also implicit identification. By implicit identification, I mean the subtle body language and sociological clues that all persons engaged in transactions use (both consciously and subconsciously.) There is not a waitress or convenience store clerk on the planet that will not begin "identifying" the ability of a customer to live up the implicit social contract of commerce based upon their attributes (appearance, cleanliness, socially accepted standards of behavior, etc). This is not the real-world as we'd like it to be. This is the real-world as it is.
I don't believe this changes radically as we move to the social realm of interactions. Rightly or wrongly, people make "identifications" of nearly everyone in their surroundings. Some of these "identifications" are wrong, and some are right -- but all are done. The bottom line of the real-world is that the human animal, at a subconscious level, *identifies* its surroundings (probably as a remnant of survival mechanisms). Anonymity -- or the "state of being unacknowledged" --- is a near impossibility in the "real-world."
All of that nasty, real-world talk aside --- the question now becomes: Should the online world reflect the real-world, or not?
As a side note to that question, I wanted to point out some of the really interesting things happening over at OpenID -- specifically, a multitude of vendors cooperating around a common goal (user-centric identity), and a "bounty program" for building OpenID code.