Earlier in the weekend, Microsoft acknowledged that there was a breach, and their official statement was that they were “aware that someone has altered the YouTube channel devoted to Microsoft videos,” with further assurance that the software giant had been working with YouTube in order to make sure that everything returned to status quo after that. It took hours for Microsoft to regain control, and they have been hard at work aiming to restore all of the original content.
No idea on how this security breach happened, but if it happened before, it definitely can (and will) happen again in the future – although we know not who the victim will be, nor what kind of visual havoc the perpetrator(s) will wreak.