Backorders: "Allow qty below 0" and "Allow qty below 0 and notify customer" difference?

I can't seem to tell the difference between these two product variant settings.  It looks like the"OrderPlaced.CustomerNotification" message template is sent to the customer in both cases.  What am I missing?  Thanks in advance.

Ok after looking at the source I figured it out.  For others...

The difference is only visible to the customer if the "Display Stock Availablilty" is checked on the product variant.  So "Allow qty below 0" displays "Availability: In stock" to the customer. "Allow qty below 0 and notify customer" displays "Availability: Out of Stock - on backorder and will be despatched once in stock." to the customer.  Unfortunately the notification email to the customer is the same in both instances.

I think despatched is spelled dispatched. :-)

Id  LanguageId  ResourceName  ResourceValue
3140  1  Products.Availability.Backordering  Out of Stock - on backorder and will be despatched once in stock.