Commercial mail receiving agency
A commercial mail receiving agency ("CMRA"), also known as a mail drop, typically operates as a Private Mail Box Operator.
A customer of a CMRA can receive mail and other deliveries at the street address of the CMRA rather than the customer's own street address. Depending on the agreement between the customer and the CMRA, the CMRA can forward the mail to the customer or hold it for pickup.
A customer may wish to use the services of a CMRA for privacy; for example, a person running a home-based business may not wish to disclose his or her residential address. Alternatively, a customer in one community may contract with a CMRA in another community with a better known or more prestigious address.
A CMRA is able to receive parcels shipped by means other than a postal system; some postal operators, such as the United States Postal Service, are not. CMRAs also usually provide ancillary services such as copy or courier services. Many CMRAs will discount their other prices for mail box subscribers. The use of a CMRA may render the delivery of mail at a later time of day than it would at a Post Office box.
Some CMRAs offer an online post office, providing a means to access mail over the internet.
Companies that offer Office Suites are CMRAs. Before signing a lease with an office suite company, the lessor should check what the policy is. BUYER BEWARE: Per the United States Postal Service (USPS) forwarding your mail is the responsibility of the CMRA:
DMM 507.2.2.7 Mail Addressed to CMRA customers: Mail addressed to an addressee at a CMRA is not forwarded through the USPS. The CMRA customer MAY make special arrangements for the CMRA operator to remail the mail with payment of new postage. A CMRA must accept and remail mail to former customers for at least 6 months after termination of the agency relationship. After the 6 month period, the CMRA may refuse mail addressed to a former customer. 
- DMM 507.2.2.7 USPS Mailer Services available at: http://pe.usps.com/Archive/PDF/DMMArchive0315/507.pdf