Yukon - Cures World Hunger
This article is another example of what's wrong with the (over)buzz around Yukon. First of all, data access is not the only thing that middle tier components are used for. Thus the article could be very confusing to the uninitiated. Second, it oversimplifies the issue. We use a set of middle tier components to do all of our XSLT work, because transforms create a significant drain on web server resources. So pulling the XML out of the database is just the first step - then you have to do something with it, right?
So the XML datatype in Yukon, which is awesome, is one tool in the toolkit, but in my mind does not reduce or eliminate the need for middle-tier applications to do their fair share of the heavy lifting. XML in and of itself is mostly useless on a web site unless transformed into HTML or some other format.
I've also yet to be convinced that just because you can store XML in your database, that it's the right thing to do in all situations. I think it all depends on what front-end applications are going to make use of that data, and whether or not you have that transform layer in place.