Attributor Acquired By Digimarc

San Mateo-based Attributor, which develops software to protect electronic books from online piracy, has been acquired by Digimarc Corporation. Financial terms of the buy were not announced. Digimarc is a developer of digital watermarking technology. Attributor's backers included Amicus Capital Draper Richards, First Round Capital, JAFCO American Ventures, Selby Ventures, and Sigma Partners.