The best selling PC game of all time is The Sims. Market research firm, NPD Group only began tracking online subscription in February 2008. As of June 2008, they do not track microtransactions or digital downloads.[1] Issued quarterly, the Video Game & PC Game Subscriptions Report will be based on data collected from over 3 million survey participants and include information on online subscriptions to MMO games and digital downloads. According to NPD Group, online subscriptions generate $1 billion annually. [2]