How doest the bitcoind command "move" work?
I think it refers to the accounts having a shared pool of money. When account A gets a deposit, the account gets a tally and it goes into the pool. When account B gets a deposit, the account gets a tally and it goes into the same pool. Moving money from A to B doesn't actually move the money address-wise, just changes the tallies. So if account A withdraws MORE than account A had deposited, part of that money will come from account B's deposit.