actions (commonly referred to as the 'no power playing' rule). Alternatively, Bob may be required to write something like the following: This allows Joe to respond to the action without contradicting the post. Depending on the rules established on the forum, role-playing and story can be pushed forward through moderation by a gamemaster, specific rules (often existing role-playing game systems), or by mutual agreement between players. Some games allow members of any writing proficiency to join, while others may require members to provide a sample of writing for review before allowing participation. In addition, a minimum word-count for each post may be required in order to encourage more detailed writing. Forums that cater to all levels of role-playing may have specific sections for various difficulty levels. Characters In general, each player plays and develops his or her own character. Characters may be original creations of the player, or may be based on a character taken from canon if the setting and rules provide this option. Each community may have its own rules regarding the process of character creation and either allow characters to be liberally created and used with minimal review, or require characters to undergo a review process in which administrators examine the character application and decide whether to approve or reject the application. In many cases, characters are regarded as belonging to the players who created them, and others are not allowed to make drastic changes to them without the creator's prior consent (referred to as god-modding). In addition to standard characters, games may also incorporate non-player characters (NPCs). Some NPCs have recurring roles, while others appear only briefly to aid in the writing of a scene. The use and control of NPCs varies widely among role-playing games. Setting Games vary in the degree to which the setting is established; some go as far as to include a virtual "world" to roleplay in, while others allow players to improvise the setting as they progress. Settings may be derived from novels, TV shows or movies (often resulting in collaborative fan-fiction) or may be original and unique to the game. Style Play-by-post games are frequently written in the third person perspective due to the fact that multiple players must share each scene, each with his or her character as the focus of attention. Common online game terms such as OOC (Out of character) or OOG (Out of Game) are used