Mac does it again

Writing a post in Blapp, which uses the default Mac OS X text editor window as far as I can tell, I stumbled across some hidden knowledge. This thing uses Emacs keys! Holy crap, how cool! By accident, I forgot what editor I was in and hit Ctrl-a to go the the beginning of a line. By gum, it did it! For a second nothing seemed unusual, until I realized I wasn’t using Emacs. So I hit Ctrl-e, voila, I’m at the end of a line. Damn! I went back to the beginning, and hit Ctrl-k, and the line disappeared, and Ctrl-y put it back. I love it! Am I the last to know this, or is this common knowledge?