I only heard the term toon when WoW started to become popular, but that's not to say that the term hasn't been around before that. I for some reason, whether it be the lack of skill that WoW players tend to have and the horrible "know it all" attitudes about MMO's cringe whenever people use terms that WoW made more mainstream. Toon being one of them, also aggro being the other one. A large population call tanking "holding aggro" which I guess is true since its holding aggravation, but just seems lame.

Obviously as you can tell I'm bias towards any phrases that WoW made popular purely because of the annoying kids I had to deal with playing other MMOs. The phrase, "OH IN WOW IT WAS DONE LIKE THIS AND IT WAS SOOOOO MUCH BETTER!!!!111!". So yeah, I'm bias. I said it.