They refer to what kind of *.app they use usually in Mac OSX. Here's my list of such apps:
- Chemr.app (HTML Help Viewer)
That's all about *.app, and there're other more apps used in terminal. I've been trying to use platform-free apps, which I can use at least in both Windows and Mac. For me, Mac OSX is just an easy-to-use and good-looking UNIX OS.
So, here's my profile page. Why don't you share your favorite apps on that site?