Bioware have updated their offical site with a piece on story-telling in MMOs.
More information.Creating great stories in video games is a hallmark for both BioWare and LucasArts. Star Wars: The Old Republic marks the beginning of a joint effort between these two companies to bring epic storytelling into a massively multiplayer online game. We believe that there are four pillars of the roleplaying experience: progression, exploration, combat, and story. Achieving a high degree of quality in each of these will create a rich, challenging, and emotional gameplay experience. Among massively-multiplayer online games, story hasn’t always received the same level of attention given to the other pillars. Star Wars: The Old Republic brings a new dimension to the MMO experience by putting story front and center.