A single Microsoft account can be used for accessing your Windows 8 PC, Windows Phone, Xbox 360, Outlook.com, SkyDrive, Skype, Office and many more services. Microsoft is finally rolling out optional two-step verification for Microsoft accounts to help keep your account more secure.
Two-step verification is when Microsoft asks you for two pieces of information anytime you access your account — for example, your password plus a code sent to a phone or email on file as security info. You can enable this capability at https://account.live.com/proofs/Manage.