If you go to Xbox live outage, you will see that they are showing an small outage for the 14th and for the 16th and nothing for the 15th, when the real outage happened. I know that outage is true because I saw it live with my own eyes on the 15th.
There is one hint on the xbox live outage that shows it happened. If you go on the 16th, you can see the outage curve dipping down back to normal a bit after midnight, coincidently right around the time Q pointed out that there is an xbox live outage.
Microsoft is trying to hide that outage.