Is it illegal to sell spam messages?

It is illegal to sell spam messages. Spam contains obscene, insulting and threatening information. No organization or individual may use the telecommunication network to produce, copy, publish or disseminate information containing the contents of spreading obscenity, pornography, gambling, violence, murder, terror or instigating crimes, insulting or slandering others, and infringing upon their legitimate rights and interests. If the case constitutes a crime, criminal responsibility shall be investigated according to law; If it does not constitute a crime, it shall be punished by the public security organ and the state security organ in accordance with the provisions of relevant laws and administrative regulations.

One of the 253rd articles of the Criminal Law of People's Republic of China (PRC).

Whoever, in violation of the relevant provisions of the state, sells or provides personal information of citizens to others, if the circumstances are serious, shall be sentenced to fixed-term imprisonment of not more than three years or criminal detention and shall also or only be fined; If the circumstances are especially serious, he shall be sentenced to fixed-term imprisonment of not less than three years but not more than seven years and shall also be fined. Whoever, in violation of the relevant provisions of the state, sells or provides others with personal information of citizens obtained in the course of performing their duties or providing services shall be given a heavier punishment in accordance with the provisions of the preceding paragraph. Whoever steals or illegally obtains citizens' personal information by other means shall be punished in accordance with the provisions of the first paragraph. Where a unit commits the crimes mentioned in the preceding three paragraphs, it shall be fined, and the persons who are directly in charge and other persons who are directly responsible shall be punished in accordance with the provisions of the preceding three paragraphs.