pubsubhubbub is an open-source protocol that establishes a Publisher-Subscriber agreement between feed servers (pub) and subscribers (sub) via a broker (hub).  It is thus an extension to the existing RSS & Atom protocols for feeds. With this, subscribers will no longer have to keep polling the feed URL, but instead will be notified of updates. Publishers will specify a hub address as part of the feed specification, and all subscribers will register themselves with the hub (instead of the feed itself). The publishing tool will notify the hub of updates, which will in turn efficiently multicast the update to all subscribers. Continue reading Jargon: pubsubhubbub →