XRP is not an IOU
.with Ripple, instead of your IOU's being trapped and controlled by a central entity, you can move them [your IOUs] freely
In Ripple, an IOU is not a means by which you can buy something now, and pay later. It's a representation of actual assets you own. When you exchange those IOU's, the asset balance is transferred to the new owner. The IOU simply determines who now owns that balance.
So you're telling me that it actually is an IOU?
No, not at all. XRP can be stored without counter-party risk and doesn't require trust to send. Thus, no IOU ever need be created for it. It already exists within the Ripple network as an asset. IOU's are representations of balances you hold, with 3rd parties. Exchanges, banks, paypal, etc.