You first start out in the Nexus as a Peasant, which is the phase of the game where you are learning about the different features, and go through the Tutoraial quests. At level 5, you must choose a path, and cannot gain any more experience until you do so. In the past, this restriction did not exist - allowing the existence of insight 99 peasants!
As a peasant you are limied in many aspect of the game. For example you are unable to have a mailbox to receive messages, when you post on a board it will indicate that you are a peasant, and many other restrictions.