Something I'd say would be useful, would be if each delivery could be assigned multiple categories.
I'd love to be able to select the categories "Personal", "Incoming" and "Gift" for the Christmas gifts I order on eBay; and "Business", "Outgoing" and "Tools" for a shipment of equipment I'm sending at work ...
I'd also say that "Personal", "Business", "Incoming" and "Outgoing" could be like main categories for sorting, while Gifts/Books/Food/Flowers/etc. could be sub-categories!? Since, yeah, in 999 out of 1000 cases, I would like to sort only according to "Personal", "Business", "Incoming" and "Outgoing" (maybe the users could select which categories that should be the "main" categories ...?)