PubSubHubbub, for those not in the know, is a server-to-server protocol for
notifying interested parties of events they’re interested in. Notifications are
pushed out to subscribers via HTTP web hooks, which offers efficiencies over polling-based solutions. With
PubSubHubbub, your server finds out about events in near real-time, without
having to determine the optimal polling interval or repeatedly fetch individual
activity feeds that haven’t changed.
We’re happy to announce that it’s now possible to subscribe to three
types of YouTube user events via PubSubHubbub: video uploads, new
subscriptions, and video favorites. The subscription requests need to be made
on a per-user basis, so you will only receive updates for specific users that
you’re interested in.
Your code can look for our PubSubHubbub hub address in the href attribute of the top-level <link rel=’hub’> element in uploads, subscriptions, and favorites feeds. For example,
the feed http://gdata.youtube.com/feeds/api/users/GoogleDevelopers/uploads?v=2 exposes the hub address in the <link rel=’hub’
More details on the PubSubHubbub can be found in the specification document. If you’d like your server to receive YouTube user event updates via
PubSubHubbub, this list of libraries is a good place to start.
-Jeff Posnick, YouTube API Team, in conjunction with the PubSubHubbub