Sure: This tier means that you are committing to purchase this item when it arrives. This tier will be placed in front of the others as they are committing to purchase and we are committing to do everything possible to supply their request. If this commitment is not followed thru on, we will place your email on a list that may no longer commit at this tier. You will be contacted when the items are available for purchase.
Maybe: This tier means that you would like a chance to purchase this item when it becomes available, but are not committing to the purchase. We will notify you when the item is available for purchase and give you first notification when we make it generally available. We are not guaranteeing that one will be available by the time you are to be notified. You will not be notified at all if none are available when the time comes.
Notify: This third tier is simply for those that would like to be notified when a product is generally available. We are not guaranteeing that one will be available by the time you are to be notified. You will not be notified if none are available when the time comes.