There are lots of ways to metagame, including:
- Using out-of-character knowledge for your in-character benefit, generally regarded as a bad thing
- Discussing mechanics during a session, which runs the gamut from useful and fun to a terrible idea
- Considering the rules in a way that your character probably wouldn’t, which I consider to be common to most RPGs, and often just fine
- Sharing mechanical tips with other players, a real mixed bag — acceptable in some games and groups, but not in others
- Maximizing mechanical benefits, even when that contradicts how your character “should” be played, which is sometimes unavoidable
And of course, all metagaming discussion is fundamentally a discussion about players: as the GM, you can metagame, but so much of your job is metagaming that instances where you doing are unacceptable are few and far between.
If you’re a big jerk and use your rules mastery to take advantage of your players, playing NPCs in ways that just don’t make any sense as a result, that’s a bad thing — but setting aside bad GMs and bad GMing practices, metagaming behind the screen is quite different from metagaming on the other side of it.
One thing I’ve noticed is that metagaming is much more acceptable in some RPGs than others — D&D, for example. It’s hard not to metagame in 4e, since the game is so tactical and minis-focused that it almost demands a level of metagaming.
Which begs the question: Is the definition of metagaming different for some RPGs than others? And the follow-up: Is “bad metagaming” also defined largely by the game in which it takes place, with a behavior that would qualify as bad metagaming in one game being A-OK in another? (I say yes to both.)
And: The other big component of what sorts of metagaming are considered acceptable is your group — what flies in some groups won’t fly in others. I’d argue that those two components — RPG and group — are the basic elements of setting boundaries with regard to metagaming, including what’s acceptable and what isn’t. But are there other components?
Whatever you consider metagaming, and regardless of how you look upon it based on your group, game of choice, and situation, there has to be a line in there somewhere — a line beyond which you’re always going to say, “Hey, that’s not cool.” Where is that line?
And when it’s crossed, how do you broach it with your players?