Taxonomy of Knowledge

David Weinberger's video (based on his new book Everything is Miscellaneous) represents a whole series of new powerful ideas. Equaly interesting are his series of interviews with physicist Neil DeGrasse Tyson, Markos Moulitsas Zúniga(founder of he Daily Kos), Arriana Huffington (founder of the Huffington Post), Jimmy Wales (co-founder of Wikipedia).
The main threads running through all of these is how everything has changed. "Web 2.0 changes everything" is a common rallying cry among Educational bloggers, but the how is often missing. I believe that David Weinberger is starting to put his finger on it. According to him, there are three orders of data. There is the data itself, say the pictures in an archive. There is metadata, the card catalogue. But when data and metadata are digital, they become interchangeable. For example, if you know that Charles Dickens wrote a Tale of Two Cities, you can Google and the four or fifth hit gives you the text of the A Tale of Two Cities. Conversely if you knew the line, "It was the best of times, it was the worst of times", but were unsure of its source, you can Google the phrase and see that it was written by Charles Dickens. Weinberger's important observation is that metadata is what you know. Data is what you don't.
In terms of Web 2.0, Weinberger mak. es two observations. Firstly that all taxonomies are arbitrary. There is no perfect order, waiting to be revealed. If everyone can organize their own knowledge in any way they see fit, that is incredibly liberating. The Web 2.0 tool that allows users to do this is tagging. As I was writing this I realized that tagging is a constructivist tool. It allows people to attach their own meaning.
Secondly, he notes that traditionally editors have exercised power by controlling what goes on the front page of a newspaper. Thanks to Web 2.0 tools, everyone is their own editor and can use tools like NetVibes to pick what stories they want to see, and in what order. To me that is a revolution on par with Martin Luther's "Every man is his own priest," and sums up very well how Web 2.0 changes everything.