1. A method of managing a marketing campaign using a computer system, the method comprising: determining, using a computer system, an identifier for a first marketing campaign; performing a first campaign step of the first marketing campaign, the first campaign step being directed at a plurality of customers, the identifier applying to the first marketing campaign with regard to each of the plurality of customers; encoding, using a processor in the computer system, the identifier for the first marketing campaign in an order number to be included in the first campaign step, the order number being unique to a first customer of the plurality of customers that is targeted by the first campaign step; including, in the computer system, the order number in the first campaign step such that the identifier can be detected in a response by the first customer to the first campaign step, in which response the first customer places an order corresponding to the order number; providing that the response to the first campaign step from the first customer can be received, at the computer system, through any of a plurality of communication channels, the plurality of communication channels including at least mail, a public computer network, fax and electronic mail; receiving, at the computer system, the response to the first campaign step from the first customer through one of the communication channels, wherein the response includes the order number encoded with the identifier for the first marketing campaign, the order number indicating that the response is received from the first customer and that the response pertains to the first marketing campaign; detecting, using the computer system, from the received response the identifier encoded in the order number that is included in the first customer's response; using the detected identifier in matching, in the computer system, the response with the first marketing campaign; generating, using the computer system, and storing in a computer memory a first object that represents the first customer's order in response to the first campaign step and contains information from the response; servicing the first customer's order using the order number; and using the information in the first object to match, in the computer system, the first object with the first marketing campaign.