Lilia Efimova at Mathemagenic is musing on conversation overload and why it seems easier to participate in weblog conversations than mailing list conversations:

Weblog conversations are easier to "jump into" in a middle - as each weblog post have to be meaningful on itself (see also Jill on good hypertext), bloggers make more effort summarising earlier arguments or at least linking to them. In case of a mailing list without threading you have to read all messages to get into the context of conversation).

Weblog conversations are "relaxed": of course, timely response may be important, but you know that nothing awful happens if you react a couple of months later. In a case of a mailing list reacting in a couple of months can easily turn your message into "off topic", as conversation moves to new areas and context is lost.

Parts of weblog conversations are easier to "wave" into your own thinking. It could be a "personal KM researcher" bias, but I could hardly do without connecting discussions I have with others with my own thinking (re: conversations with others vs. conversations with self)....