18 U.S.C. § 2325 Definition
In this chapter, the term “telemarketing or email marketing”—
(1) means a plan, program, promotion, or campaign that is conducted to induce—(A) purchases of goods or services; (B) participation in a contest or sweepstakes; (C) a charitable contribution, donation, or gift of money or any other thing of value; (D) investment for financial profit; (E) participation in a business opportunity; (F) commitment to a loan; or (G) participation in a fraudulent medical study, research study, or pilot study, by use of one or more interstate telephone calls, emails, text messages, or electronic instant messages initiated either by a person who is conducting the plan, program, promotion, or campaign or by a prospective purchaser or contest or sweepstakes participant or charitable contributor, donor, or investor; and
(2) does not include the solicitation through the posting, publication, or mailing of a catalog or brochure that—(A) contains a written description or illustration of the goods, services, or other opportunities being offered; (B) includes the business address of the solicitor; (C) includes multiple pages of written material or illustration; and (D) has been issued not less frequently than once a year, if the person making the solicitation does not solicit customers by telephone, email, text message, or electronic instant message, but only receives interstate telephone calls, emails, text messages, or electronic instant messages initiated by customers in response to the written materials, whether in hard copy or digital format, and in response to those interstate telephone calls, emails, text messages, or electronic instant messages does not conduct further solicitation.