What is the term for a sales campaign that is conducted through the mail?

The term for a sales campaign conducted through the mail is commonly referred to as "direct mail marketing." This approach falls under the broader category of direct marketing, where businesses communicate directly with consumers to generate a response or transaction. Direct-response marketing specifically involves soliciting a direct reply from the consumer, often through a specific call to action included in the mailing, such as asking them to place an order, request more information, or visit a website.

In this context, direct-response could refer to any marketing effort intended to elicit an immediate response, which can include mail campaigns. This makes it an appropriate answer, as the question implies a focus on a mail-based campaign that aims for responses. Hence, the emphasis on direct-response highlights the intention behind the marketing strategy, distinguishing it from general outreach methods like telemarketing or online advertising.