On Tuesday June 27th from 0200-0600 PT Xbox Live will be offline for maintenance. As a result, the ‘My Xbox’ section of Xbox.com will be unavailable, and the Xbox forums will be in read only mode (you won’t be able to post.) The remainder of Xbox.com will be available.
This is for maintenance, there are no new features that will appear when the service comes back online. This is all for server maintenance…nothing more, nothing less.