By mistake, when using Notes, I started killing and yanking instead of cutting and pasting and it worked. Same seems to be true for Pages. What gives? I don't think I have ever tinkered with the standard settings (at least directly).
Those key bindings are programmed into the standard text handing routines by Apple. Unless the programmer goes out of their way to write a text input library on their own, you get those key bindings for free.
Same as the close/minimize buttons and much else that is similar between programs. Much of a program comes from Apple's frameworks and SDK.
2Shows the inheritage. OS X is NeXTStep which was designed on a Unix platform - at that time Emacs was one of the most powerful tools available to Unix programmers, so those Unix programmers who implemented NeXTStep were usually quite familiar with Emacs Jan 6, 2013 at 9:24
1Good example of applications that don't respect the keybindings: Microsoft Office.– slhckJan 6, 2013 at 12:57
Many large programs that implements a cross platform code base or advanced tools like Word and Chrome generally write their own text handling and rendering views. You can usually tell these programs by checking for emacs key bindings and for the system dictionary tool - control - command - D– bmike ♦Jan 6, 2013 at 14:52