I’ve seen the demo of Denim and I’m much more bullish on that kind of thing than Bill is. At the risk of putting words into his mouth, I’m guessing that — from his point of view as someone who’s used just about every UI sketching and prototyping tool under the sun — he’d reiterate that it’s really hard to outperform pencil and paper. But when he says that, he means that the person using pencil and paper is really competent not only at making hand-drawn sketches, but also at using them to facilitate the dialogue with prospective users which is where the real action is.

I just heard a great podcast in which David Heinemeier Hansson (37signals) talks about why he thinks it’s important to require designers to work in HTML (rather than Photoshop, etc.). The idea is that it’s important to constrain the interface to fit with the medium early in the design process. Of course, he’s talking about building software that will ship this year vs. long range research, like Bill is doing. Interesting listen, anyhow: http://www.hanselminutes.com/default.aspx?showID=82