Twitter continues to ride high. Facebook has grown a lot, but newcomer Line seems set to overtake it. Social game companies Gree and Mobage have shifted their overseas expansion into high gear. And Mixi finally admits that it needs to try harder to understand what its members want. In this month's column, we look back at the big battles fought in the Japanese social-media scene over the past year.

Twitter's new "Lifeline" feature was launched in September in Japan — the first region in the world to receive the service that suggests which official government Twitter accounts should be followed if disaster hits. Seeing how the popularity of Twitter surged in Japan immediately after the Great East Japan Earthquake and tsunami on March 11 last year, it is no surprise the service was developed here.

Along with positioning itself as an essential service in times of trouble, Twitter has been localizing new features from its global version into Japanese, with no dramas.