It’s a new marketing technique book publishers are testing: “direct cellphone contact” with favorite authors of books for teens. Examples given by USATODAY include The PrincessDiaries series and the The Sisterhood of the Traveling Pants. “The teen girl audience was chosen to test the program [the latest by HarperCollins] because cellphones are considered their main source of communication. Ads promoting the mobile club are running on teen sites such as thewb.com and begin this week at seventeen.com, cosmogirl.com and ellegirl.com,” USATODAY reports. The ads send them to author site MegCabot.com, where they sign up to receive recorded messages from the PrincessDiaries author and up to two text messages from her a week. The venture is part of a growing use of mobile technology in the entertainment industry (to wit earlier items here this week about all types of games coming to mobiles).