Jamie Zawinski was using it before working at Netscape: https://archive.is/vzeWI (not linking it directly since he doesn't like it)

"Back before the Computing Dark Ages of the Nineties began, I hacked on Lisp Machines. If you've still got an Explorer or Symbolics, you might find some of the stuff I wrote in the good old days useful. It's archived in the CMU AI Repository."