Online games are more compulsive than fun.

Two of the main areas of fun in a game are the activities of the game itself, and the interaction with other players. Single-player games rely entirely upon making the mechanical activities of their games fun, and are quite good at it. For online worlds, there are two main approaches - creating worlds rich with player to player interaction, and worlds heavy on mechanical, goal-oriented activities.

The current market leaders in the US MMP industry are activity games. Some of these games are so light on player to player interaction that you can actually turn off your ability to see other players. The tragedy, of course, is that this style of gameplay is popular because of one amazing success story. That success story is EverQuest, a game that was originally designed as a pay per minute game, so one of their design goals was to compel players to spend as much time as possible online. They rely heavily upon incremental visible gains and a persistent and advancing goal - a carrot on a stick, compelling players to log in and perform the same activities as long as possible.

The fun inherent in a well-crafted mechanic or activity is the basis of the single-player game industry. However, the number of single-player games that are consistently fun for more than 100 hours is very small. People get bored and they move on to the next game. Online worlds that rely solely upon mechanics or activities for their fun are doomed to failure - players will put in their 100 hours and leave.