Used in the army! Good mean of knowing who to ask what, as higher rank means more experience!
What I devised is the following schema, but it's entirely debatable:

Clan Friend - Does what it says. Considered as no rank at all.

Recruit - A clan member's rank; Everyone's a member, and so is he.

Corporal - Actually knows what "KoA" means. Given after 6 months in the clan.

Sergeant - Gives orders, and sometimes people listen. Given 9 months after received the Corporal rank.

Lieutenant - Feels absolutely at home, and sees nothing odd with asking you to make him coffee. Given 12 months after receiving the Sergeant tank.

Captain - Given to junior staff, such as events. Has the ability to magically make people disappear when clicking their name in the CC.

General - Given to senior staff, such as site admins. Has the ability to magically make people disappear permanently when clicking their name in the CC.