http://www.rfc-editor.org/rfc/rfc3863.txt
RFC 3863: Presence Information Data Format (PIDF), H. Sugano, S. Fujimoto, G. Klyne, A. Bateman, W. Carr, J. Peterson2004-08-01T23:00:00-00:00This memo specifies the Common Profile for Presence (CPP) Presence Information Data Format (PIDF) as a common presence data format for CPP-compliant Presence protocols, and also defines a new media type "application/pidf+xml" to represent the XML MIME entity for PIDF. [STANDARDS-TRACK]