How Google Reader Sharing Contributes to Real Time Search

    August 6, 2009
    Chris Crum

Google has announced that Google Reader has begun adoption of the PubSubHubbub protocol for shared items. This is a simple, open, server-to-server web-hook based pubsub (publish/subscribe) protocol, as defined on this Google Code page.

Here’s a visual overview of what that means:


 "All shared item pages have feeds, and now all of those feeds will ping a hub (and there’s a <link rel="hub" …/> element in them)," explains Mihai Parparita on the Google Reader Blog. "This means that if you (as a web app developer) would like to more efficiently and quickly monitor Reader shares, you just have to subscribe at the hub to be notified of changes in real-time. If you want to learn more about PubSubHubbub and how it works, see the site and protocol definition."

Google names FriendFeed specifically as a place that takes advantage of such pinging. If you have added your shared items to your FriendFeed account, you and your friends will see them there in real-time. This means they will appear in FriendFeed’s real-time search engine.

Adding the PubSubHubbub support was one of the famous 20% projects of a few Googlers. They cite the project as a contributor to making the web a faster place, which of course is a big initiative of Google these days.