Lanefan
Victoria Rules
This bginrs up a good point.Yup. It will indeed mean different things to different people.
For me, taking on a role most often means a role in a story....a persona, a specific character...and I play the game essentially advocating for that character within the story.
In a typical RPG you're not just playing the role of your character, you're also advocating for it against opposing forces provided by the game and-or setting and-or GM (and-or other players, sometimes). This differentiates our type of RPGs from, say, improv theater games; where you're just as much playing a role but the whole advocacy point is largely missing or irrelevant.