Section 17538.45 of the California Business and Professional Code allows Electronic Mail Service Providers to restrict or prohibit use of their equipment for Unsolicited Electronic Mail Advertising (UEMA), when the equipment is located in the state of California. It further provides for liquidated damages of $50 per message received. reddit.com uses equipment located in California, and the reddit.com policy is that Unsolicited Electronic Mail Advertising is prohibited.

Text of section 17538.45 of the Business and Professional Code of the State of California, copied on July 17th, 2008. Check with the California Law website for the current text (search for section 17538 or "unsolicited" in the Business and Professions Code).

    17538.45.  (a) For purposes of this section, the following words
    have the following meanings:
       (1) "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.
       (2) "Unsolicited electronic mail advertisement" means any
    electronic mail advertisement that meets both of the following
    requirements:
       (A) It is addressed to a recipient with whom the initiator does
    not have an existing business or personal relationship.
       (B) It is not sent at the request of or with the express consent
    of the recipient.
       (3) "Electronic mail service provider" means any business or
    organization qualified to do business in California 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.
       (4) "Initiation" of an unsolicited electronic mail advertisement
    refers to the action by the initial sender of the electronic mail
    advertisement.  It does not refer to the actions of any intervening
    electronic mail service provider that may handle or retransmit the
    electronic message.
       (5) "Registered user" means any individual, corporation, or other
    entity that maintains an electronic mail address with an electronic
    mail service provider.
       (b) No registered user of an electronic mail service provider
    shall use or cause to be used that electronic mail service provider's
    equipment located in this state in violation of that electronic mail
    service provider's policy prohibiting or restricting the use of its
    service or equipment for the initiation of unsolicited electronic
    mail advertisements.
       (c) No individual, corporation, or other entity shall use or cause
    to be used, by initiating an unsolicited electronic mail
    advertisement, an electronic mail service provider's equipment
    located in this state in violation of that electronic mail service
    provider's policy prohibiting or restricting the use of its equipment
    to deliver unsolicited electronic mail advertisements to its
    registered users.
       (d) An electronic mail service provider shall not be required to
    create a policy prohibiting or restricting the use of its equipment
    for the initiation or delivery of unsolicited electronic mail
    advertisements.
       (e) Nothing in this section shall be construed to limit or
    restrict the rights of an electronic mail service provider under
    Section 230(c)(1) of Title 47 of the United States Code, any decision
    of an electronic mail service provider to permit or to restrict
    access to or use of its system, or any exercise of its editorial
    function.
       (f) (1) In addition to any other action available under law, any
    electronic mail service provider whose policy on unsolicited
    electronic mail advertisements is violated as provided in this
    section may bring a civil action to recover the actual monetary loss
    suffered by that provider by reason of that violation, or liquidated
    damages of fifty dollars ($50) for each electronic mail message
    initiated or delivered in violation of this section, up to a maximum
    of twenty-five thousand dollars ($25,000) per day, whichever amount
    is greater.
       (2) In any action brought pursuant to paragraph (1), the court may
    award reasonable attorney's fees to a prevailing party.
       (3) (A) In any action brought pursuant to paragraph (1), the
    electronic mail service provider shall be required to establish as an
    element of its cause of action that prior to the alleged violation,
    the defendant had actual notice of both of the following:
       (i) The electronic mail service provider's policy on unsolicited
    electronic mail advertising.
       (ii) The fact that the defendant's unsolicited electronic mail
    advertisements would use or cause to be used the electronic mail
    service provider's equipment located in this state.
       (B) In this regard, the Legislature finds that with rapid advances
    in Internet technology, and electronic mail technology in
    particular, Internet service providers are already experimenting with
    embedding policy statements directly into the software running on
    the computers used to provide electronic mail services in a manner
    that displays the policy statements every time an electronic mail
    delivery is requested.  While the state of the technology does not
    support this finding at present, the Legislature believes that, in a
    given case at some future date, a showing that notice was supplied
    via electronic means between the sending and receiving computers
    could be held to constitute actual notice to the sender for purposes
    of this paragraph.
       (4) (A) An electronic mail service provider who has brought an
    action against a party for a violation under Section 17529.8 shall
    not bring an action against that party under this section for the
    same unsolicited commercial electronic mail advertisement.
       (B) An electronic mail service provider who has brought an action
    against a party for a violation of this section shall not bring an
    action against that party under Section 17529.8 for the same
    unsolicited commercial electronic mail advertisement.