Advertising can take multiple forms. It is no wonder that there is often confusion about whether a mailshot is actually advertising as defined in competition law, and hence is subject to the strict conditions that apply to sending advertising emails (e.g. in Section 7of the German Act Against Unfair Competition (UWG)) or in Article 13 of the European Data Protection Regulation for electronic communication). The sender is often not aware that they are actually sending an advertising email. This article uses examples to help clarify when an email is considered to be an advertisement.