California Code, Revenue and Taxation Code - RTC § 6379.8

(a) There are exempted from the taxes imposed by this part the gross receipts from the sale of, and the storage, use, or other consumption in this state of, mailing lists, if the contract regarding that mailing list restricts the purchaser to a single use of the mailing list.

(b) For purposes of this section, “mailing list” means a written or printed list, series, set, group, or aggregation of names and addresses of, and occasionally, other information concerning persons, including, but not limited to, potential customers or donors, that is intended for use in circulating material by mail. A mailing list may be in the form of a manuscript list, directory, Cheshire tape, Dick tape, gummed labels, index cards, or other similar means of communication. “Mailing list” also includes a magnetic tape or similar device used to produce written or printed names and addresses by electronic or mechanical means.