Yeah I'm a little surprised not to see the article touch on keyboard layouts (e.g. DEC, Sun) that had Ctrl in the home row where Caps Lock is on a PC keyboard. While Emacs may have been initially developed on the "space cadet" keyboard, it really became popular on Unix systems that often had an even-easier-to-reach Ctrl key. And to this day swapping caps lock with a modifier remains fairly common.
