Mich. Comp. Laws § 445.1772

Sec. 2. (1) A person shall not send an advertisement to another person by means of a facsimile machine without first obtaining, by means other than by a facsimile machine, the consent of the person who will receive the advertisement. (2) Consent may be given by telephone to a particular vendor or by general notification to marketing or industry trade associations. (3) Consent to have a facsimile machine telephone number published in a directory or disseminated in any other manner shall not be construed as consent to receive an advertisement under this act.