When you rent a box from the UPS store and Mr.Mail and places like that, and you have box #555, you can give your address as:

123 Fourth street
#555
Anytown USA

which gets around the No P.O. Boxes delivery limitations. You used to be able to list the address as "Suite 555" or "Apartment 555" but that's been outlawed due to all the fraudulent activity it encouraged.

Now you can't pretend it's anything. But you have a street address and that's all you need for UPS or Fedex delivery.

And of course when you rent a PO Box at the Post Office it's just a box and a zip code, no street address.

Actually that reminds me, the dread Airborne used to drop-ship large packages coming to me AT THE POST OFFICE and let the mailman deliver them! They had some kind of arrangement with the Postal Service. What a ridiculous situation that was. Usually I wasn't home for delivery, and so I ended up going to the Post Office to pick up my Courier Packages!. One more reason I used to avoid Airborne like the plague.