I think in terms of publishing and communication blogging and even microblogging still stands for: I publish, you read. It's not: We discuss. It's more like: Hear what I say. I want your attention. (Not really your opinion or reaction)
Comments in blogs imply a hierarchy of author vs. commentators. Links between blog articles do not allow detailed references. You can only link to the whole article, not single paragraphs or sentences (except if the author would provide you with anchor tags for them). Of course interesting is the kind of dialog in Twitter using @username. However, it's a closed system and you're quite limited in the way you're able to link (you cannot do something like <a href="@username">my friend</a> for example).
I propose the term granular dialog for a new way of web communication. Let's think of a classic blog entry as elements of microcontent (paragraphs, images, even single sentences). Microcontent in the sense 
Anil Dash describes it: "... content that conveys one primary idea or concept, is accessible through a single definitive URL or permalink, and is appropriately written and formatted for presentation in email clients, web browsers, or on handheld devices as needed.".
What's important here is that by permalinking microcontent, single elements of large content types become referenceable. In that sense a more granular dialog is possible.
By the way, we do not need Google Wave for this. We can do that with the web itself, in a more standardized, open way.