Emacs makes a pretty good example from my perspective, but if you haven't used it I suppose it makes little sense. Perhaps AutoCAD from what I understand, but I

Emacs makes a pretty good example from my perspective, but if you haven't used it I suppose it makes little sense. Perhaps AutoCAD from what I understand, but I don't have enough experience with extending it to say for sure. It's not that you have to extend it yourself, the point is to make it possible. Annie in accounting (can't believe you got away clean with that one :) might ask someone else in the company to help her add a shortcut or whatever, or the company might hire an outside consultant. There's an entire gradient from non-technical to expert that's effectively shut out from modifying most software. Now I'm as guilty as anyone, getting a client to pay for an advantage they can't imagine the consequences of isn't happening much. But I can certainly see the value.