XMPP is Extensible Messaging and Presence Protocol and it is an open XML technology for real-time communication which powers a wide range of applications including instant messaging, presence and collaboration. XMPP is a set of standards that allows systems to talk to each other. XMPP is used widely across the web but is often unadvertised. The protocol or standards are looked after by the XSF. Message part of XMPP is the the Instant Message (IM) sent between clients. XMPP has been designed to send all messages in real-time using a very efficient push mechanism; whereas existing web based mechanisms often make many unnecessary requests introducing network load, and are consequently not real-time.
Suresh M