The popular microblogging service Twitter on Thursday launched a Japan-based mobile version, hoping to penetrate a country where other U.S. social networking sites including Facebook and MySpace have failed to capture much ground.

Japanese is Twitter's sole foreign-language platform so far, and the company's efforts here indicate it's serious about making it big in Japan — and eventually all over the world.

Twitter teamed up with Tokyo-based Internet firm Digital Garage Inc. in early 2008. It launched a Japanese-language platform for cell phones and other mobile devices in spring 2008, and hired a Japan country manager earlier this year.