If you use Hotmail or Live – do this ASAP! Google has had this for a while and this is the best way to keep your account (and life) secure. Someone with access to your primary email can get into all sorts of online accounts.

Add Two-Factor Authentication to Your Microsoft Account
Two-factor authentication is one of the best things you can do to secure your online accounts. Today, Microsoft is rolling out this important feature for Microsoft accounts—the key to Outlook.com, Windows 8 PCs, SkyDrive, Skype, Office, and more. Here's how to enable it on yours.