I REALLY APPRECIATE Six Apart's launch of the TypePad PubSubHubbub hub because it means my blog will update in real time across various networks (i.e., Google Reader, FriendFeed, SuperFeedr and LiveDoor). Because it's a Six Apart service, I don't need to use a plug-in. I just have to add a single line to my Atom template because I use advanced templates on my Inside View blog. Here's the line needed to the atom.xml file>
<link rel="hub" href="http://hubbub.api.typepad.com/" />
PubSubHubbub is a "simple, open, server-to-server web-hook-based pubsub (publish/subscribe) protocol as an extension to Atom and RSS". The PubSubHubbub protocol is decentralized and free. No single company controls it and anybody can run a hub, ping (publish) or subscribe using open hubs.
There is a considerable amount of information on the Google Code page and an active discussion group as well.
More: "What API to Choose"
