Definition: Microsoft account

A single sign-on that enables users to log in to Microsoft services such as Office 365, Skype, Outlook.com, Xbox Live, OneDrive and the Microsoft online store with the same username and password. Users already have a Microsoft account if they signed up for any of these services previously. In 2012, the Windows Live ID was renamed Microsoft account.

Synchronization to All Devices
When logged into a Microsoft account, software and media downloaded from Microsoft's online store, along with settings, contacts and documents can be synchronized onto all the user's Microsoft devices.

Microsoft vs. Local Account
In order to download content, users must be signed into their Microsoft account, and they will be prompted to switch to it or sign up for one if not previously created. When users switch back to their local accounts (from the User Accounts control panel), all downloaded content from Microsoft is available for use.