Summary: For some reason Matt Mullenweg started paying attention to Dave Winer. It's one of the worst ideas he's ever had, <i>and he's the idiot who wrote Wordpress</i>, so that's really saying something.<p>After a year or so of uselessness and a few epic flameouts from Dave, they'll probably implement PubSubHubBub on Wordpress.com, and rightfully not waste effort trying to make it work for self-hosters. With any luck, they'll stop serving duplicate feeds and go pure Atom at the same time.
Brett Slatkin on the difference between PubSubHubBub and rssCloud:<p>from <a href="http://jy.typepad.com/jy/2009/07/pubsubhubbub-rsscloud.html" rel="nofollow">http://jy.typepad.com/jy/2009/07/pubsubhubbub-rsscloud.html</a>:<p>In a nut-shell, rssCloud's subscriptions are merely a way of redistributing pings to subscribers. We think this is still on the publishing side of the problem and does not simplify the life of a subscriber. With rssCloud, subscribers must re-fetch the feed to see if it's changed. In contrast, Hubbub delivers the actual changes to the subscriber so they have no more work to do. This makes it much easier to subscribe, and has some nice properties when it comes to scalability.
So in plain english without all the hype, it's RSS pushed from the server instead of pulled by the client.<p>How are they doing it over http without thousands of connections being open and closed constantly on the server per second? Are they just announcing to a central server and the client only polls the one server for any one of thousands of blogs they could be subscribed to?<p>I guess I'll look at the code tomorrow.