Su diveintomark trovi un eccellente riassunto sulla discussione tra bloggers su cosa sia un weblog e che cosa esattamente lo caratterizzi. Alcune citazioni:
The blogging/counterblogging form pretends to function as a conversation, but, unlike E-mail or instant messaging or any kind of threaded discussion forum, the effect is one of talking at people rather than with them. But you’re talking at them in public, rather like chatting on a cellphone at the mall, only in this case third parties stand a good chance of reading both sides of the conversation.
… Now, according to the egalitarian mythos of the Web, anyone can publish. You skip the step of requiring an editor and publisher, but no one is willing to skip the step of requiring an audience.
However, I feel he is dead on about the nature of weblogging conversation. It is most definitely talking at people. That they occasionally happen to talk back at you (and poke you with a wide variety of digital poking mechanisms) does not make it a conversation in any traditional sense. This is not to say the form has no merit — it does — but I think the lack of a concrete audience means that it lends itself to a certain type of writing (pontification, of which I am notably guilty, especially recently). It’s good at conversation-starting but bad at actual conversation itself.