What is the difference between metal stored with OWNx and a "pooled" account?

There are several differences, but "unallocated" versus "allocated" is the central difference between a "pool account" and OWNx.

Allocated:

This is how OWNx operates. Allocated silver or gold is very simple. The metal is held on behalf of the account holder under a custody agreement. It is held at a depository and is registered in your name as your property. The metal is neither the property nor liability of the depository. With this type of agreement, it is not subject to any third party creditors. You initiate every transaction via secure.OWNx.com. At the time the transaction is completed, ownership transfers from OWNx to you and is held in custody at one of our non-bank depositories, until at your instruction, you decide to sell your metal back or initiate delivery exclusively via secure.OWNx.com.

Pool:

OWNx does not operate using pool accounts, though other dealers do. In a pool or “unallocated” account the account holder does not have title to the silver or gold he/she has "purchased." Rather, in reality what the investor has "purchased" is an asset or claim to a certain amount of silver or gold. So essentially, in an unallocated account you are promised a defined amount of silver or gold. ("Your" metal is simply a liability on the balance sheet of the bank or company). There may or may not be physical metal held to back the purchase and if there were it could conceivably be leased out to generate interest for the bank or company with the expectation of it being returned if needed. What this means is, you could find yourself standing in line with all of the other unsecured creditors in the event of financial problems or insolvency of the purveyors of this type of account.