Jabber is the popular and original name of a chat protocol later known as
XMPP. It is structured similar to
e-mail but with a focus on supporting instantaneous communications and presence notifications. Unlike electronic mail, which was originally designed to work with disconnected servers, Jabber assumes that servers are always available, although users might not be. In practice, as
Internet access has become nearly universal in the
developed world, this is also the case for electronic mail.
Jabber is based on
XML, which some consider a blessing in that it is readily extensible (via
JEPs) while others consider one of its top two failings given its verbosity and weight when compared to lighter
binary protocols. The centralized nature of Jabber and lack of
multi-casting are also considered deficiencies in the protocol.
Jabber, in part of its open and standardized nature, has become a popular protocol for companies implementing their own chat system. It is the platform upon which
Google,
Live Journal, and
Facebook.com have built their chat systems upon.