The w3c recently published their long-overdue and much-anticipated Architecture of the World Wide Web, Volume One
(Here's the story from internetnews.com)
One of the formal recommendations which caught our eye was for the implementation of content negotiation. As the authors point out, content negotiation:
[P]romotes consistency, as a site manager is not required to define new URIs when adding support for a new format specification.
Of course, content negotiation not only makes your URIs cool and gets you w3c bragging rights. It can also let you serve multi-lingual sites using a single set of URIs, and serve different file types (for instance, different image formats) according to the user's browser preferences (or “q values,” as they are known in HTTP talk).
As the Apache admins out there no doubt already know, they get this functionality for free in mod_negotiation. And, if you'll permit us a quick brag to celebrate this auspicious occasion: Our PageXchanger is the only implementation of content-negotiation for IIS --at least, the only one that we're aware of.