"X-" Prefixes deprecated by RFC 6648.

[Charles Plessy <plessy@debian.org>]

Dear all,

I would like to share with you the recently published RFC 6648, which
deprecates the use of "X-" prefixes in "application protocols"

BEST CURRENT PRACTICE

Internet Engineering Task Force (IETF)                    P. Saint-Andre
Request for Comments: 6648                           Cisco Systems, Inc.
BCP: 178                                                      D. Crocker
Category: Best Current Practice              Brandenburg InternetWorking
ISSN: 2070-1721                                            M. Nottingham
                                                               Rackspace
                                                               June 2012


           Deprecating the "X-" Prefix and Similar Constructs
                        in Application Protocols

Abstract

   Historically, designers and implementers of application protocols
   have often distinguished between standardized and unstandardized
   parameters by prefixing the names of unstandardized parameters with
   the string "X-" or similar constructs.  In practice, that convention
   causes more problems than it solves.  Therefore, this document
   deprecates the convention for newly defined parameters with textual
   (as opposed to numerical) names in application protocols.

Full text available at http://tools.ietf.org/html/rfc6648 

Cheers,

-- 
Charles Plessy
Tsurumi, Kanagawa, Japan