The effect of action in games is designed to be a seemingly simple, but difficult to do abstract and highly scalable system. But World of Warcraft created the buff system to unify the design concept. This concept can be very simple to connect some systems, such as: Channel Magic, just cast a buff, and set the duration and the middle of some effects, the client to do some special effects, server handling damage. I also have a conjecture that, in World of Warcraft, equipment is also the same as buff, belong to a category, equipment is also available, and produce effects, but the default of these categories of buff is static. Superimposed on a person's property. This system is very easy to implement, and when you do two development, you can choose the parameter configuration or the full script type. From the extensibility analysis of World of Warcraft, this two-time development is most likely to build a tool generation system based on scripting. For example, you can define a buff buff: Demon Armor { permissible Occupation: Warlock Level: 62+ function Damage calculation () { Modify Mana/sec} Use the skill to connect this buff. Similar equipment is also very convenient to define Camp system: to describe the relationship between a game character is to let them belong to the enemy or to us, But such a definition is rudimentary. For the World of Warcraft has a huge number of people and history of the game, this greatly increased the difficulty of two development. The camp system is simple: There are many camps in the world that set the camp for each person to belong, and its own reputation for the rest of the camp, when the reputation of the other faction is neutral, you can not attack the people of the camp, but also not the task, but also through a number of settings to allow it to attack, and to deflect the prestige. Attack and be attacked endIt all depends on your reputation with others, which makes the MMO design simpler