There are two kinds of players in Massively Multiplayer Online role-playing games. One kind of player is primarily concerned with maximum advancement, whether it be through leveling their characters to the highest possible level, or gathering the most powerful equipment and items which further increases the ability and prestige of their character in the game. Since many of the most powerful rewards are available through a type of quest called a "raid," these players are often referred to as "raiding" players.

The other type of player is more concerned with exploring the game world, trying to succeed at the various categories of game activity, including improvement of secondary skills, crafting, player vs. player battles, and completing various quests on a very relaxed schedule. These kinds of players are known as "casual" players.

The difference between these two types of players is essentially the amount of time either is prepared to invest in reaching their goal. Raiding players are usually prepared to invest whatever amount of time is necessary, often many many hours each week, in order to advance their character to the highest power level possible in the shortest amount of time. Casual players more often view the game as a pastime rather than a goal in itself. The differences between these types of players can be thought of almost as the difference between amateur and professional or professionally-minded athletes. One plays the game, has a good time, and then goes on to something else. The other plays the game, and invests considerable effort in getting better at the game in order to compete at a much higher level.

In Blizzard Entertainment's World of Warcraft, for example, the original game provided players a maximum attainable level of 60. Once a player had reached level 60, prior to the expansion of the game, it was no longer possible for them to gain levels. Level 60 players did, however, have the opportunity to join very large groups of other players to participate in quests to "dungeons" (known as instances in the game itself) populated with only the most powerful monsters guarding the most valuable treasure in the game known as "epic" items, signified by purple lettering in their descriptions.

More casual players continued to have the opportunity to do quests, but in instances which were designed around smaller groups of players, and with somewhat less valuable treasure. The chief difference between the two kinds of groups was the coordination required in order to defeat the monsters. In a raid instance, it was necessary for groups of up to 40 people to work together in a highly synchronized cooperative fashion in order to succeed. The margin for error is very narrow in a raid instance, and it was often necessary for the groups to make numerous attempts before succeeding in defeating even one of the monsters.

In the casual dungeons, however, there was a much more forgiving environment for groups without the highly precise synchronization of a raid group. If an individual player made a mistake, failed to heal at the right time, or allowed a monster to escape and alert other monsters to attack the players, it was very often possible for that group to survive and successfully complete the instance. This makes it possible for groups that had never worked together before to join other players and participate in an instance quest.

The dedication required to make a successful attempt at a raid instance is considerable. For this reason, groups wishing to complete raid instances often form permanent associations in the game called "guilds." Guilds organize their players to make their raid attempts as efficient as possible, making absolutely sure they have enough fighters, healers and spellcasting characters in their groups so they are not left without sufficient capabilities in a given category during a battle.

Guilds also make it possible to coordinate a large group of players and their activities outside the raid instances. Making sure their members are properly equipped is a high priority for guilds. Having a sufficient supply of potions, food and specialized armor for their players is important, so guilds often encourage their players to take up necessary trade skills to build and gather those items.

Because of the reduced risk in a casual instance, it is only rarely necessary for players to need specialized equipment, so there is little need for any coordinated effort to gather those items for other players.

Once the players in MMORPGs reach maxiumum level, the difference in capabilities and power between casual and raiding players is significant, but is usually proportional to the amount of time each type of player has invested in the game. It can literally take months for a raiding player to successfully complete a raid instance, between the weeks of leveling, the multiple attempts to learn how to defeat the monsters in the instance, the time required to gather money to pay for supplies. No such time investment is required for a casual player, since there is no specific goal for a casual player. Whether they defeat an instance or not, they are deriving enjoyment from the game.

Games with directed goals that require a large time commitment are relatively recent inventions, and as skill levels increase, it is likely players will continue to seek professional status. There are already professional tournaments for various video games, and it is possible that MMORPG "events" like the first defeat of a very powerful monster, may become popular soon.