(Cross-commented on the Peterme.com site)
Great post on peterme.com discussing the importance of business metrics (and the user behaviors they measure) as a tool to frame-up and catalyze design brainstorming. I’ve seen how this process can work to both generate some design ideas, but more importantly, convey to business leaders that the design process is rooted in, ahem, reality, that the design/creative process is actually trying to drive business value.
I can definitely see how this approach helps the design brainstorming process. But, as a "business guy" and not a designer, I see this process as helping in at least a couple important ways:
1) communication and collaboration between the two teams – This should ultimately help produce a better design because it gives the teams a common language to use to solve site and design challenges.
2)Design Solves Problems – this process makes explicit the assumption that design is about solving problems: for the user AND the company. I feel like this might be the most valuable insight for us business weasels. Design should be a part of the earliest product/solution development discussions, to understand what behaviors are implied or important to the success of the product/solution.
Jim Cuene 
And by “design” I assume you (and Peter) of course mean “design and content” – ahem.
Every time I sit down with clients to discuss the copy that will replace the “lorem ipsum” appearing on all their pretty web design templates, this exact topic comes up. Just because we (the business) think something’s important (our mission, our values, our key competitive differentiators laid out in iambic pentameter) doesn’t mean our users actually, you know. CARE.
Always, from start to finish, in design/copy/tools/campaigns/whatever: we MUST examine user goals, tie them to business objectives, and bridge the gap in a way that ultimately makes users feel smart and satisfied. Which in turn will make more money for businesses.
So, yeah. There’s no more hiding behind your art, people. ‘Cause now we can measure it. Sorry.