Indiana Code Title 24. Trade Regulation § 24-5-22-8

(1) Send unsolicited commercial electronic mail and fail to use “ADV:” as the initial four (4) characters in the subject line of the electronic mail. This subdivision does not apply if any of the following apply:

(2) Send unsolicited commercial electronic mail and fail to use “ADV:ADLT” as the first eight (8) characters in the subject line of the electronic mail if the unsolicited commercial electronic mail is any of the following:

(3) Send unsolicited commercial electronic mail and fail to provide a means for the recipient easily and at no cost to the recipient to remove the recipient's name from the sender's electronic mail address lists.

(4) Send unsolicited commercial electronic mail to a recipient who has asked the sender to remove the recipient's electronic mail address from the sender's electronic mail address lists.

(5) Provide to a third person the electronic mail address of a recipient who has asked the sender to remove the recipient's electronic mail address from the sender's electronic mail address lists. This subdivision applies to a third person who is a part of the sender's business organization. This subdivision does not prohibit providing a recipient's electronic mail address to a third person for the sole purpose of inclusion of the electronic mail address on a do-not-mail list.