Maryland Commercial Law Section 14-3002
(a)   This section does not apply to an interactive computer service provider or a telecommunication utility to the extent that the interactive computer service provider or the telecommunication utility merely handles, retransmits, or carries a transmission of commercial electronic mail.
(b)   A person may not initiate the transmission, conspire with another person to initiate the transmission, or assist in the transmission of commercial electronic mail that:
(1)   Is from a computer in the State or is sent to an electronic mail address that the sender knows or should have known is held by a resident of the State; and
(2)   (i)   Uses a third party's Internet domain name or electronic mail address without the permission of the third party;
(ii)   Contains false or misleading information about the origin or the transmission path of the commercial electronic mail; or
(iii)   Contains false or misleading information in the subject line that has the capacity, tendency, or effect of deceiving the recipient.
(c)   A person is presumed to know that the intended recipient of commercial electronic mail is a resident of the State if the information is available on request from the registrant of the Internet domain name contained in the recipient's electronic mail address.
(d)   An interactive computer service provider:
(1)   May block the receipt or transmission through its interactive computer service of commercial electronic mail that it reasonably believes is or will be sent in apparent violation of this section; and
(2)   May not be held liable for an action under item (1) of this subsection that is voluntarily taken in good faith.