Almost any game, MMO or RPG, that involves XP tends to involve a bit of grinding, and one player's grinding is another's gameplay, since I know some people who have outrageous amounts of tolerance when it comes to killing mobs repeatedly for XP, reputation or a rare drop. As Catalyst8 above points out, one can even grind other players in PvP in WoW. While you can be very passive in that regard, only doing as little as needed to get credit for being present, is that any different than gimping around in a game of Modern Warfare to unlock more weapons. If a lot of people aren't considered grinding on multiplayer unlockable-style games like that, I don't know what else to call it.
So I do wonder why this grinding poll was limited to MMOs, since as the replies are already showing, we've got plenty of other games that have grinding in them. I know quite a few players who enjoy a game like WoW but really don't like to rep or XP grind, and they'll just accomplish quest objectives or run instances to level, but especially with instances, the distinction begins to blur. It might be helpful to try and hammer out a definition of just what grinding is, and we'll probably find it's a very relative term.
