James Tauber, Don Park, and Dave Winer are discussing how to tag blog-to-blog conversations. The idea is that blog entries for a particular conversation are assigned an agreed-upon category and that a conversation aggregator is used to moderate the conversation.
To add my own two cents to this thread, conversation aggregators (as well as the participating blogs) should make use of "reply on my blog" links.
Also, on naming the conversation: When replying to blog entries which are not yet designated as being part of a thread, an identifier is generated, perhaps inviting responses from a list of fellow travellers. This identifier could be based on the entry, or selected through a dialog which would assist the blogger in forming a Google-unique word combination.
It warms my heart that ideas for blog-to-blog conversations can be improved upon in the context of a raging RSS vs. Atom debate :)