The latest NerdTv on Dave Winer has this bit on agility:
Dave: ... The big deal was the mind of Mitch. I mean what Mitch taught me was he would take - he'd sit - you could sit him down with a piece of software, and he would reach into his shirt - jacket pocket, take out a little notebook, put it down next to him on the computer. He would sit there, type a little bit, use it, and then he would take a little note, and he would sit down and type a little bit more. He would use it some more, take a little note. And when he was finished, he had a to do list. And that was if you did all those things that were on the list, and you brought it back to him, he would do it again. Okay?
And then this idea of successive refinement of user interface, and of using, of actually using the software - the developer actually using the software - as a way of improving it, because the feeling was, well, you know, and this was where Personal Software went way wrong. Okay? They started hiring all these guys from the Pentagon, and they had all this real engineering culture for specifying software. And their feeling was, “Well, you just never - it was all hands off.” The engineer never actually used the software. It was crazy.
I mean, and so Mitch's attitude was quite the opposite, is that if you don't use the software, you're just simply never going to get there. And he was right. And I adopted everything I could learn from him, every - every idea there with - and it was a key element for success. I mean up until that point - and then the next thing, which nobody had taught me, was to actually have the guts to sit there while a user uses your software. Okay, and don't say anything.
Bob: It's terrifying, isn't it?
Dave: It is, no, it's incredibly depressing and revealing at the same time. I mean the first time I did it, the guy said - I realized - he didn't even have to say anything before I understood exactly what the problem was. He said, “The software doesn't say anything to me.” And he was right. It just sat there. Didn't actually say anything. Well, there's a clue. Maybe the software should say something.