Twitter cofounder Biz Stone once said, "There will never be ads on Twitter.com." Note that Stone never said anything about Twitter.jp. News.com reports that Twitter has launched in Japan, with ads. "Ads are important," Twitter backer Joi Ito said. "It's always harder to add ads later. So we're launching with them in Japan." What a tiresome PR game: Are ads any less important in the U.S.? If Stone wants to add them to Twitter.com, he and cofounder Evan Williams should go ahead. The ads in Japan actually link to the advertiser's Twitter feed. WIth that kind of arrangement, Robert Scoble and Jason Calacanis will surely sign up as charter sponsors.