2 Way Syndication
Amongst all the talk about Google's IM client, I saw Russel Beattie's post that described the XMPP protocol.
You don’t send individual XML documents per message, instead you open up a socket and start writing one XML document keeping the socket open the entire time, as you need to send more messages, you keep adding XML stanzas to the document. You do this both on the up and down stream. To end the conversation, you simply end your document’s root tag.
This got me thinking about the SixApart Atom stream; the difference here is that the conversation is one way. It makes me wonder if there's a useful way to combine XMPP and syndication to do something like what SixApart is doing.