Xbox Live Tops Six Million UsersLast year at E3, Microsoft pledged that it would double the subscriber base of Xbox Live from three million users to six million by the end of June 2007 - a milestone it has now reached four months ahead of schedule. To mark hitting six million users on the service, Microsoft has released an update on key statistics related to Xbox Live - revealing that as well as the 2.3 billion hours spent playing games on the service since its launch in 2002, Live is also coming into its own as a communication system, with over 2,000,000 voice and text messages sent between users every day. Halo 2 remains the most popular game on the service to date, followed by Gears of War in second place and Xbox Live Arcade title Hexic HD in third. However, while Microsoft revealed a number of statistics related to its Gold (paying) subscribers - such as the fact that on average, a Gold subscriber has 22 friends in his friend list - the company remains silent on the question of how many of its six million Xbox Live users are paying a Gold subscription, and how many are using a free Silver account. Silver users can download patches and content updates, chat with friends and access Xbox Live Marketplace, but cannot play multiplayer games online. Todays announcement did, however, include an interesting update on the popularity of the Xbox Live Arcade service - and more specifically, on what the most popular games on the service to date have been. Street Fighter II Hyper Fighting is the most-downloaded game on Arcade (based on downloads of the full version), followed by card title UNO in second, Bankshot Billiards 2 in third, and iconic launch title Geometry Wars: Retro Evolved in fourth. Other games which have proved successful on the service are Texas Hold Em, PAC-MAN, DOOM, Contra and Ultimate Mortal Kombat 3, which fill out the chart from fifth place through to ninth place respectively. Overall, Xbox Live Arcade has seen 25 million downloads - and Microsoft estimates that almost 70 per cent of users who have connected their console to the network have downloaded from Xbox Live Arcade.