According to the National Arbitration Forum, Microsoft
has purchases several Xbox related domain names from Cheng Juan of China. The names included are xboxcompanion.com, xboxphone.com, xboxlivetv.com, and xboxtablet.com. The mysterious xbox8.org and xbox8.us were also included in the dispute.
While most likely something to do with Microsoft's integration of Windows 8 with Xbox. It's still tempting to assume that Xbox 8 is Microsoft's next generation console, however.