Marketing by means of e-mail, so-called e-mail marketing, is the equivalent of direct marketing in the offline sector, i.e. sending advertising material by post.

The sending of advertising by e-mail is subject to legal restrictions. In Germany, various laws regulate the sending of and certain mandatory disclosures in business e-mails (e.g., the Unfair Competition Act, UWG, contains provisions on “advertising using […] electronic mail” in Section 7 on unreasonable harassment, and the Electronic Commercial Registers and Register of Cooperatives and the Business Register Act, EHUG, stipulates that certain imprint information must be included in a business e-mail), in Austria the Telecommunications Act (TKG) and in Switzerland the Telecommunications Act (FMG) regulate this form of advertising. For example, since March 1, 2006, unsolicited e-mails in the business-to-business sector have also been regarded as spamming.