(
Instant
Messaging and
Presence
Protocol) The working group of the IETF that specializes in instant messaging. The IMPP group developed the CPIM abstract model, PIDF presence document and spawned working groups for the APEX, PRIM and SIMPLE IM protocols, the latter coming to fruition with major support from various vendors. See
presence,
CPIM,
PIDF and
SIMPLE.