Normally a virtual world contains several towns and places for players to explore. The following screenshot is from the 51mole, a Flash virtual world for children in China. The whole virtual world contains around 25 places with different themes. Some are inside mountains, some are castle, and some are snowing. Players seldom get bored inside such a large and content-rich virtual world.
The virtual world can sometimes be very large. We cannot put the whole world into one SmartFoxServer room when it grows big. Putting a large area into one room means that there are more users inside the room. More users means many more broadcast messages for every player's action and this will cause performance and bandwidth problems.
If all parts of the world belong to the same room, all broadcasted events of the avatar will be accessed by all players. On the other hand, in the partitioned world, the broadcast messages are sent only to those players that...