Microsoft has announced that the number of members of its online network, Xbox Live, has reached 6 million, four months earlier than expected.

Xbox Live enables members to chat with other gamers, play demos, watch trailers and download entertainment content including television shows and full-length films from the Xbox Live Video Marketplace. On the official Xbox 360 site it’s revealed that the top-selling Xbox Live title for the Xbox 360 is Halo 2, followed by Gears of War and Hexic HD in third place.

A total of 2.3 billion hours have been spent playing games on the service since its launch in November 2002. Microsoft said that over 2,000,000 text and voice messages are sent each day between friends using the service. The company said the average Gold level subscriber of Xbox Live, who receives exclusive and early access to content, has 22 friends on their friends list.

Over 70 percent of Xbox Live members have used Marketplace to download content leading to 135 million downloads since the Xbox 360 launch.

South Park fans will also be excited to learn that the first ever high-definition episode of the show is now available as a free download from Marketplace.

Microsoft is also claiming success for its Xbox Live Arcade platform, which has now exceeded 25 million downloads from its catalogue of classic and original Xbox 360 games. The most popular Xbox Live Arcade title is Street Fighter II’ Hyper Fighting, with Bankshot Billiards 2 as second best selling.