When we first declared our ill-advised independence from Starfleet, the other officers and I were unsure as to the value of a rank structure at all aboard a floating expression of anarchy. After several hours of spirited discussion, followed by a long period of sleeping in wildly distorted positions in conference room chairs, we decided to keep a rank structure. Not because we wanted to give people rewards and responsibility, but because deep down we all wanted people to know who the cool guys were.
The resulting rank structure was little different on the surface from that used by Starfleet. Most of the names remained the same, and we even kept the same insignia so that our guests would not have to think too hard about it. The primary difference is in the meaning of those ranks.
In Starfleet, as in most military organizations, rank is a reward for performance, an automatic dividend of long and faithful service, and an indicator of the amount of responsibility and respect a given member may command. Aboard the Casual, rank is simply a thing passed out on a whim or based on specific monetary or otherwise acceptable bribes given to the on-duty Commanding Officer.
That being said, there is a pecking order within the rank structure that we try to keep in mind when we care. It goes like this:
The rank of Ensign carries no rights or responsibilities, except as their masters the Senior Officers permit. They are useless peons.
The position of Yo!Man! or Yo!Woman! is one of great honor and responsibility, and it can be granted to any member for any reason by any Senior Officer. That Yo!Man! or Yo!Woman! is then bound to said Senior Officer in ways that cannot easily be imagined, and is expected to make the Senior Officer's welfare and pleasure their primary concerns (except when that would mean that they can't have any fun themselves). This position is like, but shall not be confused with, slavery.
An honorary rank bestowed upon an Ensign for services rendered to the Senior Officers. They have the same rights and responsibilities as an Ensign.
Specific responsibilities within the department afflicted with. Lieutenants are useful peons.
An honorary rank bestowed upon a Lieutenant responsible for assisting the Commander of a department within his departmental responsibilities. This is a leader of peons.
Has the responsibilities of overseeing all activities that his department is connected with. The rights of a Commander are almost limitless, as are the powers of the rank. Commanders are, however, required to be generally fun at all times, lest he anger the Commodore, which may be cause for accidental death or dismemberment.
Responsible for coordinating all departments and Commanders into an intricate and totally perplexing web of interconnected interdependencies and functions whereby the Casual shall be capable of performing her mission without too much trouble. The Captain is in titular command of the vessel at all times, 24 hours a day, and must be capable of continuous function without rest or sustenance while maintaining a wonderfully charming demeanor and a casual attitude towards life. The Captain is required to be fully competent to perform the function of any officer, guest, or piece of hardware aboard the ship at a moment's notice. Also responsible for having an instant and witty response prepared for any question or comment made by the Commanding Officer.
The rank of Captain is typically thrust upon an unsuspecting Commander during a period of delusion or inebriation.
Responsible for Universal Knowledge regarding all functions within the Cosmos, and the status thereof. Also responsible for making sure that everyone is having a really good time. Command power equal to that of any major deity. A Commodore (while on duty) is answerable only to himself, and must bear that burden with a smile and a great deal of optimism.