"Microsoft Your Account" is company's Billing Account Management portal, and allows Hotmail, Office, Zune, Xbox 360, and Windows Phone users to track their subscriptions and transactions in one single billing portal.
Microsoft is using the "Microsoft Account" branding in Windows 8 instead of Windows Live ID, and Microsoft's latest billing portal appears to confirm that the company is working towards some type of consolidation and single point of billing and logon.
Microsoft Your Account, via Rafael Rivera