Commercial Email and Spam:
Unsolicited Commercial Email Advertising Law of 2003, codified at California Business & Professions Code, Division 7, Part 3, Chapter 1, Article 1.8 (§§ 17529 and following)
Electronic Mail Service Providers are empowered to sue to enforce their policies prohibiting spam email in California Business & Professions Code, Division 7, Part 3, Chapter 1, Article 2 (§17538.45)
The Anti-Phishing Act of 2005, codified at California Business & Professions Code, Division 8, Chapter 33 (§§ 22948 - 22948.3), makes it unlawful for a person to use the internet or email to deceive another person into providing personally identifying information (i.e. "phishing")
Telemarketing & Telephonic Anti-Solicitation:
General regulation of telephonic sellers, codified at California Business & Professions Code, Division 7, Part 3, Chapter 1, Article 1.4 (§§ 17511 - 17514)
California "Do Not Call" Registry, codified at California Business & Professions Code, Division 7, Part 3, Chapter 1, Article 8 (§§ 17590 - 17594)
Telephonic solicitations to California consumers must comply with the Federal Trade Commission's Telemarketing Sales Rule in order to constitute the basis for a valid contract - see California Civil Code § 1670.6
Faxes, Texts, and Other Media Anti-Solicitation:
General prohibition of text message advertising, which is subject to exceptions, codified at California Business & Professions Code, Division 7, Part 3, Chapter 1, Article 2 (§ 17538.41)
Prohibition of unsolicited advertisements sent from one fax machine to another, codified at California Business & Professions Code, Division 7, Part 3, Chapter 1, Article 2 (§ 17538.43)
Unlawful Trade Practices:
Unlawful trade practices are defined to include violations of California's prohibitions against unlawful forms of advertising, including unsolicited email advertising - see California Business & Professions Code, Division 7, Part 2, Chapter 5 (§ 17200)
Note: California's Supreme Court held - in Barquis v. Merchants Collection Association of Oakland, 7 Cal. 3d 94 (Cal. 1972) - that the concept of "unfair competition" has been broadened to include general consumer protection, and a prohibition against unlawful trade practices
Pornography:
California Penal Code Part I, Title 15, Chapter 2 (§ 653m) makes it a crime to use a telephone or "electronic communication device" to annoy, threaten, or send obscene language to another
Computer-related Crime:
California Penal Code Part I, Title 15, Chapter 2 (§ 653m) makes it a crime to use a telephone or "electronic communication device" to annoy, threaten, or send obscene language to another
California Penal Code Part I, Title 13, Chapter 8 (§ 528.5) makes it a crime to impersonate another through electronic means
Additional Resources:
State of California, Office of the Attorney General - Spam-Related Consumer Protection Information