In the blog post, you mention that these teams are adopting the Lean Startup philosophy of ship early and ship often. Does that mean that you've softened on the "never ever write any code without a spec" dogma from "the Joel Test"?
I've personally found that when you're doing tight iterations and continuous deployment, writing old-school spec documents feels, well, old-school.
If I can go straight from human conversation w/ whiteboard sketches to working, tested code running on production servers without creating intermediate written documents, I think I'm winning.