I've seen guild banks in Wow, or Dofus, and other MMO games.
In the guild I've been a part of, we mostly used the bank as storage; resources stored that end up not being used are wasted. Sometimes there is a free share policy, but there is always that one guy who will take stuff he does not really need and sells it.
This led me to wonder what is the original purpose of a guild bank, what do players like to use it for, and how can a game help them do it?