Guild bank characters
A character used as storage and/or a trading post by the members. Usually accompanied by a web based script to post the contents online. Bank rules depend on the guild, there is no set of default permissions.
Official guild banks
In-game guild banks have been enabled as of Patch 2.3.
- Access to the guild-bank via a Guild Vault object next to the standard bankers in the game. 
- Players with the appropriate permissions can store items and money for use by the rest of the guild.
- 6 purchasable tabs which have 98 item slots each, bags are not required for the slots. Prices start at 100, then increasingly for the next tabs, 250, 500, 1000, 2500, 5000).
- Storage of money.
- Repair NPCs will have a 'pay for repairs from guild funds' button based on guild permissions (up to withdraw limit).
- Advanced permission-system (defaults to controlled by guild leader), that can allow, disallow and limit the interaction (deposit/withdraw items or money) per tab, per guild rank. Withdrawal limits can be set up. The limit amount is in copper (not gold as the UI shows).
- Access-logs in-game showing the 25 latest money or item related withdrawals/deposits per tab.
- ^ http://www.wowinsider.com/2007/05/16/2-1-and-beyond-guild-banks
- ^ MMO Champion; Boubouille 2007-10-20. New PTR Build. Retrieved on 2007-10-20.