Screencast as development tool

I’m in the middle of the first phase of building a new webapp and like most web developers (I would bet) when I show someone what I’ve done, it’s not apparent what marvels of engineering I’ve pulled off! So, in order to actually give a quick run-down of where we’re at with the application, I thought about making a screencast of the login, profile creation, module, video upl– well, I’ve said too much already ;)

After thinking about that for a bit, I wondered if any methodologies, agile or otherwise, use screencasts specifically as a tool. I could just Google it, I know. In any case I think it’s a nice way of showing progress on the development – or bugs in the app.