jabber, also known as xmpp, is a protocol which is mostly used for instant messaging. it is an open protocol in that anybody can participate in the development. also, the jabber/xmpp network is decentralised, since everybody can run their own server. this way, no single company owns jabber or xmpp. unlike with other proprietary instant messaging networks, you can simply choose another jabber server if you are not satisfied with it and are still reachable in the jabber universe.

jabber/xmpp is developed by its authors on jabber.org. the core protocol, xmpp, is described in RFCs, namely 3920 and 3921. it is the only standardised instant messaging protocol so far. this qualifies jabber as a world wide communication protocol.