In order to make preparations for Xbox 360, Microsoft announced that Xbox Live and Xbox.com will be shut down temporarily on October 24th, with service for both resuming the following day.
Changes to Xbox Live include the Xbox Live Marketplace and a record keeping system that keeps track of your gaming achievements in every Xbox 360 game you play. While the changes will be made during the downtime, they will be invisible to gamers on Live until the console's launch November 22nd.
Changes to Xbox.com include a new site area called "My Xbox" which will list each gamers' achievements, much like the console interface. Players will be able to check stats of other players through a variety of other Microsoft services, such as MSN Spaces and the official Xbox forums. These initiatives are a part of Microsoft's emphasis on community gaming in an effort to attract more gamers apart from the "hardcore" crowd.
News source: Gamesindustry.biz