According to Dictionary.com escrow is:

  "a contract, deed, bond, or other written agreement 
   deposited with a third person, by whom it is to 
   be delivered to the grantee or promisee on the 
   fulfillment of some condition."
   (from: http://dictionary.reference.com/browse/escrow)

You will find an escrow station at Sungate that is
operated by the Merchant Council with the aim of 
facilitating the safe trade of valuable items between
mortals.

The premise is:

Alice wants to sell an item to Bob.
If Alice gives the item to Bob directly then Bob can
run away, or take days and weeks to pay for the item.

If Alice gives the item to the Merchant Council to hold
in escrow until Bob pays them she can retain some level
of control over the transaction.  When Bob pays the 
Merchant Council they release the item to him and transfer
the gold directly to Alice.  If Bob doesn't pay for the
item Alice can claim it back from the Merchant Council.

In-game mechanics
=================
* Both players must be logged on to place or redeem an item
* Items will remain in escrow for one week before being 
  sold to defray expenses.  It is up to Alice to remember
  to redeem the item before this time if it looks like Bob is
  not going to pay for it.
* The commands "place", "redeem", and "list" will work at
  the escrow station and have instructions on how to use them.
* If you redeem an item that you yourself placed into escrow
  you are charged 500 gold.  This seems a smaller risk than
  somebody running off cackling with glee clutching your 
  precious shinies.