Your Windows Live ID is essentially your online identity for all of the Windows Live services, Xbox Live, Zune and other third party websites (such as Expedia.com) that utilize Windows Live ID. If you're using Windows Live Hotmail and Windows Live Messenger, your Windows Live ID stores all your contacts and email messages. Your Windows Live ID is definitely something you don't want to have compromised and I've got several pointers - or best practices - in keeping your Windows Live ID safe.
Do not hand out your password! Don't give anyone your password to your Windows Live ID. Handing out your password to anyone is simply asking for trouble. Don't even give out your password to friends or family. I can't imagine a reason why they would need it. Just don't give out your Windows Live ID credentials at all.
Be careful giving your Windows Live credentials on non-Microsoft websites. There are some websites out there that will claim they "require" your Windows Live ID credentials for their service. Some sites use this tactic to gain access to your Windows Live ID.
Fact: Microsoft will only ask for your Windows Live ID credentials on login.live.com and nowhere
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