What are the differences between each of the Fellowship roles?
In a Fellowship, there are four roles a player can have.
Member: this is the role that a player is automatically assigned once joining a Fellowship. Members have no special authoritative permissions.
Ambassador: this role can be assigned to a member that has proven to be an exceptional asset to the Fellowship, and is appointed by either a Mage or Archmage. This person has the ability to invite and accept new recruits into the Fellowship. In a Fellowship Adventure, the Ambassador also has the right to progress the Fellowship to the next stage, once the last Waypoint of a stage has been cleared.
Mage: this is an important role in any Fellowship and can be seen as a "second-in-command" to the Archmage, and is appointed by either a Mage or Archmage. This person has all the rights of an Ambassador, as well as the rights to expel current members, along with changing Fellowship attributes (description, flag, etc.).
Archmage: this role is the highest ranking authoritative figure in the Fellowship. This person has the ability to all of the above permissions along with relinquishing their Archmage title, and even disbanding the Fellowship.