But its not for the same reason Kevin does.
I'm a crusty old Sherlock Holmes fan at heart who learned "canon" as it refers to the stories written by the person who created the character.
I am absolutely mad for "continuity." I live for retcons. I got into X-Men by the soap-opera-esque cartoon and the Age of Apocalypse crossover and I got into DC Comics with The Return of Barry Allen. What hooked me on comics was tracking down the old story references in those books. I was raised on a strict diet of continuity porn and I'm not about to give it up for anything.
But I fucking hate hearing the word "canon" to refer to it. There's something about the tone of the word. Canon is too solid. Too concrete. Canon is written in stone. Canon is strict and rigid and religious by nature.
"Continuity" is there, but its fluid. It doubles back on itself and then moves forward. It forgets itself and then rewrites itself. Continuity turns around and slips treasures in the seams right in front of your face. It can go Retro for a time or rewind and move sideways. Continuity is very much a superhero comic book word. Continuity is vibrant and growing and changing.
Canon is a dead word. These stories are alive.