I just coded a level file in XML for a game being developed in one of my classes. The same group member who was so adamant about coding the levels in XML had neglected to build an XML creation program. So there we were, trying to wade through > 10,000 lines of XML. I wanted to cry

FWIW, I've had a different experience with XMPP. Take for example XMPP Multi-User Chat (http://xmpp.org/extensions/xep-0045.html) - which outlines a rich set of interactions between occupants of a room - something I'm really glad someone else engineered for me. Plus, take a look at the XML stanzas (in the examples here: http://xmpp.org/extensions/xep-0045.html) you are sending to the server, they're really not that big or complicated. Lastly, with BOSH (http://xmpp.org/extensions/xep-0124.html) and incredible XMPP Javascript client libs like Strophe (http://code.stanziq.com/strophe/), the possibilities are pretty exciting for web apps.

A quick skim of the Multi-User Chat though... Firstly, it's 9 years old :/ why is everyone still not using it? Secondly, you can immediately tell it's ridiculously over-engineered.

  <field var='muc#roominfo_occupants' label='Number of occupants'>
    <value>3</value>
  </field>

Sorry, but you can't really look at that protocol and say it's not ugly and verbose beyond reason. The number of occupants in a room is surely used enough to deserve an encoding of less than 75 characters to specify a number.

Isn't that the whole problem with XML