PubSubHubbub, a 20% time project of two Google engineers, Brad Fitzpatrick and Brett Slatkin, launched a few weeks ago.
In addition to being a tongue-twister, PubSubHubbub is:
A simple, open, server-to-server web-hook-based pubsub (publish/subscribe) protocol as an extension to Atom (and RSS).
Parties (servers) speaking the PubSubHubbub protocol can get near-instant notifications (via webhook callbacks) when a topic (feed URL) they’re interested in is updated.
Essentially, your feed reader won’t need to poll all your feeds for updates periodically anymore, saving loads of resources. Each feed that declares a hub hands off updating subscribers to the hub, which pushes notifications when they’re available. Anyone can declare a hub for their feed to use by adding some code to the feed, and anyone can operate a hub.
The protocol will definitely speed up feed reading, and it has applications for any syndicated content and any frequency, e.g. it could be used for a micro-blogging or IM, in a much more efficient push updates mode instead of a persistent connection mode.
Check out the video from the Real-Time CrunchUp for a an introduction and demo.
There are several products using PubSubHubbub already, including FriendFeed, Google Reader Shared Items and Feedburner. Today, Google Alerts joined this list.
This blog uses Feedburner’s PingShot, so we are have been using the bootstrap hub hosted at Google App Engine for several weeks. If you check the source for our feed, you’ll find:
<atom10:link xmlns:atom10="http://www.w3.org/2005/Atom" rel="hub" href="http://pubsubhubbub.appspot.com/" />
Did you notice updates were faster? I don’t really post enough for it make much of a difference. I suppose I should have noticed, since I publish the posts and can see how quickly they appear in Google Reader.
Rich will probably implement a hub for Connect to use inside the firewall too.
A few months ago, Connect was plagued by performance issues; it was falling over every day at 0200 Pacific time. Not ideal, since we’re all asleep at that time and couldn’t bring it back up for a couple hours.
Rich and Anthony pinpointed the problem. A ton of feed readers were polling for updates at 0200, causing Connect to die. They got this issue fixed, and Connect has been humming along fine for a while (knock on wood). Intrigued, Rich decided to analyze Connect logs to see how often feed readers were polling.
We were all astonished to find 1.4 million requests for feeds this month alone.
1.4 million is a lot for us, especially considering the relatively modest web metrics for Connect for this month, only about 65,000 pageviews and 5,000 unique visits so far.
We’re still trying to figure out what this means. It doesn’t feel like feed reading has suddenly become mainstream, but maybe . . . I’m at a loss.
Anyway, PubSubHubbub seems like the perfect solution to save our servers from millions of GET requests.
Heard about PubSubHubbub? Any other ideas on how it could be used? Are you updating your blog to use a hub?
Find the comments.
Update: This post took about five hours to get into my Reader. So, I guess Reader hasn’t finished implementing the protocol yet, aside from Shared Items.