PubSubHubbub protocol for shared items. This means that instead of repeatedly requesting that Reader's shared items reload from the server, the feed automatically updates via a distributed hub model. Rather than waiting on the back and forth pings of update notifications and polled Atom URLs, feed subscribers can receive both the notification and the message from a hub.Google Reader is about to get much faster for developers. You'll be pleased to note that Reader has just adopted the
Subscribers get the latest content on their favorite feeds in near real time (sans repeated links), while publishers let the hub handle the subscription load. This distributed model allows publishers and subscribers to reduce the number of actions required to serve up feeds and is what Anil Dash eloquently describes as the Pushbutton Web.
This latest Reader effort is a 20% Google project of Mihai Parparita, Brett Slatkin and Brad Fitzpatrick. Slatkin and Fitzpatrick co-created PubSubHubbub to increase efficiency across the cloud and decentralize services. Fitzpatrick is best known as the founder of LiveJournal and co-creator of Memcached and OpenID. Given that Memcached speeds database-driven websites and OpenID decentralizes the social graph, PubSubHubbub fits nicely into the group's accomplishments.
Friendfeed is already benefiting from the PubSubHubbub experience. If you're currently sharing Reader items in your Friendfeed account, your Friendfeed subscribers can already see your updates in real time.
For more information on PubSubHubbub check out a great post by Dave Winer, the father of RSS.