Doc Searls talks about the communities of conversations and knowledge sharing around weblogs and why they're likely to succeed where knowledge management has failed. Searls refers to something Michael Polanyi writes in Personal Knowledge. Polanyi succinctly states that "we know more than we can tell." Searls adds, "what we know is tacit and what we can tell is explicit — and it is important not to mistake the latter for the former (or, for example, to insult the former by quantifying it as "intellectual capital" or whatever)." This is the point of weblogs. Not only do they attempt to create recorded conversations of the type that is normally in the tacit realm, e.g. person to person verbalized conversations, but the social connectedness of weblogs and the web creates a social dynamic where conversations are picked up, advanced, modified and transcended in the dispersed conversational space of the web. It's really quite extraordinary.
Searls also points to a presentation given by John Seely Brown, who extends Polanyi's classification of personal knowledge to the social space, showing that lots of knowledge is social. Incidentally, I'm reading Brown's The Social Life of Information so a lot of the blog and km-related writing that I'm finding is helping to bring lots of ideas that I'm incubating together.