I was asked in one of the other threads when I thought the proper context for using XP existed.
Since it didn't really relate to that thread I thought I would extract it out in to a blog.
It is here.
I would be interested in feedback to see if you agree or have a different twist on it.

When to use XP
azfar
Sorry, I am not sure why it failed.
I can maybe take a guess at why you would say you do not need to be a domain expert, since XP calls for one to be handy 24/7.
I listed it though because I have not beeen in an environment where that was not true. The teams have been small and dedicated to the same application long enough to become domain experts.
moyoz
I guess we could, but I am stating what I have seen people do when it has work, not what the recipe calls for.
Just like the RUP, I have seen it be successful as the UP. The problem with the RUP, is you never make it into the oven, because you would be adding ingredients all day.
I agree you are right when it comes to what the books say should be there, but I have not seen it happen.
If you have, that's cool. Tell us about it.
c#_novice
I try adding feedback to your blog but it kept failing.
I disagree strongly with needing to be a domain expert.
avc
Well ... would that not be changing the concept of XP in order to disagree with it
My baked alaska recipe calls for vanilla ice cream.
Last month I made it with strawberry ice cream and noone liked it....
Terrible Recipe.
:)