This is here as a formality, mostly, and I wish to make players aware of. There are three types of meta-gaming. All of which I discourage wholeheartedly.
prefix meaning 1. “after, behind,” 2. “changed, altered,” 3. “higher, beyond,”
Statistical Meta-gaming – Making decisions with a character(s) based on a statistical percentage or number, thereby determining that it should succeed, or the knowledge of the level or hit points of an NPC. These statistics are things characters do not know. You don’t walk down the street and know that the person across from you is level 4, has 20 hit points or has levels in fighter.
Foresight Meta-gaming – Using knowledge that your character does not possess to your advantage. For example, the DM has told you to make a spot check but you didn’t succeed. You therefore assume that there is something to be noticed and attempt to discover it another way, even though your character has no real motivation for searching an entire room for something he failed to see. Another form of Foresight Meta-gaming is acting on information your character does not possess. For example, if the barbarian and the rogue are aware that the rogue stole the gold from your inventory and your character is not aware of this fact, but immediately searches their pack to make certain all of their possessions are there that would be foresight Meta-gaming. Another example is not making the correct knowledge check to identify a creature, such as a pyro-hydra, but behaving as though you had made the check by utilizing your own player personal knowledge and making your character immune to fire.
External Meta-gaming – External Meta-gaming is using knowledge you possess outside of the game to influence the game (such as preparing for the encounter your DM set up before your character would be aware of the specifics of said encounter), using knowledge of reference to identify a parody your DM has created (such as knowing that the creature who is very similar to Golem from Lord of the rings, and then stealing his ring even though your character has no real motivation to steal the ring from the Golem parody), and finally bringing external sources of reference into the game (such as “I wish for a shotgun”. A character in most fantasy settings wouldn’t know what a shotgun is.) The last of these isn’t really game-breaking, but it is incredibly annoying. Your DM and players may want to have original content in their game and when you say “my character is just like Trunks from Dragon Ball Z” it can be very irritating, lame and uninteresting to the other players as well as the DM. This type of meta-gaming also includes in character references to things in the real world. Calling another character “Hitler” in a fantasy world where no such person existed would be another example of meta-gaming.
If you ever have a question about meta-gaming, you are always welcome to ask your DM.