Problem: A Microsoft account is just an email address that’s been registered with Microsoft. If you have a Hotmail, Outlook.com, or Live.com email address, you already have a Microsoft account. You can turn any email address into a Microsoft account.
Microsoft wants you to log on to Windows 8.1 with a Microsoft account so it can offer you all sorts of conveniences, such as automatic logon to SkyDrive and Metro Mail, Calendar and Internet Explorer, saving your Metro settings, and syncing your downloaded Metro apps.
At the same time, though, you have to realize that Microsoft’s keeping track of everything you do with the account -- when you log on to Windows, what you’re doing with IE, and who knows what else.