815 ILCS 511/5
As used in this Act:
"Electronic mail advertisement" means any electronic mail message, the principal purpose of which is to promote, directly or indirectly, the sale or other distribution of goods or services to the recipient.
"Unsolicited electronic mail advertisement" means any electronic mail advertisement that (i) is addressed to a recipient with whom the initiator does not have a prior or existing business or personal relationship and (ii) is not sent at the request of or with the express consent of the recipient.
"Electronic mail service provider" means any business or organization qualified to do business in Illinois that provides registered users the ability to send or receive electronic mail through equipment located in this State and that is an intermediary in sending or receiving electronic mail.
"Initiation" of an electronic mail message refers to the action by the initial sender of the electronic mail message. "Initiation" does not refer to the actions of any intervening electronic mail service provider that may handle or retransmit the electronic mail message.
"Registered user" means any individual or entity that maintains an electronic mail address with an electronic mail service provider.
"Electronic mail address" means a destination, commonly expressed as a string of characters, to which electronic mail may be sent or delivered.
"Internet domain name" refers to a globally unique, hierarchical reference to an Internet host or service, assigned through centralized Internet naming authorities, comprising a series of character strings separated by periods, with the right-most string specifying the top of the hierarchy.
815 ILCS 511/5