“Mass mailing” means over two hundred substantially similar pieces of mail, but does not include a form letter or other mail which is sent in response to an unsolicited request, letter or other inquiry.

(Amended (as amended June 7, 1988, by Prop. 73) by Stats. 1988, Ch. 1027, Sec. 1. Note: This section was added on June 4, 1974, by initiative Prop. 9, and amended on June 7, 1988, by initiative Prop. 73.)