It is harmless, and has been around for many years.
Some time ago, I queried it. There were many guesses as to its intention, but nothing conclusive
I seems it is a credential that is stored when you use any of the Windows Live products, including Windows Live Messenger, Windows Live Mail, Windows Live Sign-In Assistant, and a few other Microsoft services.
It is safe to delete the entries, but, if you are using Windows Live or any other Microsoft services on a regular basis, or Microsoft and partner items from the store. It is not recommended - They will, in any case, be recreated when you again use them.
The rather poor solution, it is said, is to uninstall Windows Live products and look for alternatives, there is absolutely no reason to do that, for security or otherwise.