Michigan Compiled Laws, Chapter 445. Trade and Commerce § 445.2502

(a) “Commercial e-mail” means an electronic message, file, data, or other information promoting the sale, lease, or exchange of goods, services, real property, or any other thing of value that is transmitted between 2 or more computers, computer networks, or electronic terminals or within a computer network.

(b) “Computer network” means 2 or more computers that are, directly or indirectly, interconnected to exchange electronic messages, files, data, or other information.

(c) “E-mail address” means a destination, commonly expressed as a string of characters, to which e-mail may be sent or delivered.

(d) “E-mail service provider” means a person that is an intermediary in the transmission of e-mail or provides to end users of e-mail service the ability to send and receive e-mail.

(e) “Internet domain name” means a globally unique, hierarchical reference to an internet host or service, assigned through centralized internet authorities, comprising a series of character strings separated by periods, with the rightmost string specifying the top of the hierarchy.

(f) “Person” means an individual, corporation, partnership, association, governmental entity, or any other legal entity.

(g) “Preexisting business relationship” means a relationship existing before the receipt of an e-mail formed voluntarily by the recipient with another person by means of an inquiry, application, purchase, or use of a product or service of the person sending the e-mail.

(h) “Unsolicited” means without the recipient's express permission. An e-mail is not unsolicited if the sender has a preexisting business or personal relationship with the recipient. An e-mail is not unsolicited if it was received as a result of the recipient opting into a system in order to receive promotional material.