Yes, here's a thought which I already voiced on irc - Peter and Lars are probably the ones to answer that question.
What about I18N?!
Imagine I pass on "Look at http://www.foobar.com/o/666" to someone. The object shows up in German to me. This person has Italian as his default language. Now there is now Italian translation for that object. The server will fall back to French because this is the default language. /o/666 now shows a French translation that is or is not a good translation of the object I intended to show to my biligual Italian friend.
So - *without* knowledge about the chosen I18N solution - did I start to worry about the approach we used for stable URLs in a *monolingual* system.
Here's a rough proposal: change the request processor so that it accepts LC_$ISO_LANGUAGE_CODE somewhere in the URL. I could pass on "http://www.foobar.com/LC_de/o/666" *and* "http://www.foobar.com/LC_it/o/666" to him and tell him..."look how bad they are at translating".
It would also give the user to alter the default language setting by just fiddling with the URL a bit.
