I did some work for a machine translation business that used Common Lisp as their "secret sauce". As they considered it a serious competitive advantage, you wou

I did some work for a machine translation business that used Common Lisp as their "secret sauce". As they considered it a serious competitive advantage, you wouldn't hear about it anywhere. I've seen this with quite a few other companies since, but that means that lots of companies could be using lisp and nobody would ever know about it.