It would be very very useful if in the customer section you could "code" a customer so when they order it would flag or identify the customer in the order section.
For Example
Lets say there was a problem order you could flag the customer so when they reorder in the future we could triple check to make sure there is not a repeat.
ID your best customers so when they order you can quickly stop and prioritize their order.
When sending Promo emails you could flag or code so those orders can be quickly ID