Yup, I remember when USPS was pushing to have all users of private mail facilities to use PMB XXX on their mail. PMB = Private Mail Box This was an effort to give a heads up to one an all (banks, credit card companies, mail order etc) that these were "real" addresses. The county clerk was hounded by news reporters when it came out that some 73 people were registered to vote and they all had the same "apartment" which was, in fact, a private mail drop!