Not to be confused with WebVTT, a W3C standard for timed text. WebSub (formerly PubSubHubbub) is an open protocol for distributed publish–subscribe communication on the Internet.[1] Initially designed to extend the Atom (and RSS) protocols for data feeds, the protocol can be applied to any data type (e.g. HTML, text, pictures, audio, video) as long as it is accessible via HTTP. Its main purpose is