an hours-long outage impacting the social media giant along with Facebook-owned Instagram and Whatsapp.The drop in Facebook's share price cost co-founder and CEO Mark Zuckerberg – who owns about 15% of the company's stock – more than $6 billion in personal wealth, knocking him down a notch in the rankings of the world's richest people.RELATED: Facebook, Instagram, Whatsapp down: Platforms 'coming back online' after outageAccording to Forbes' real-time billionaires list, the drop moved Zuckerberg from #5 to #6 on the publication's list of the world's wealthiest people with a new worth of $116.8 billion, falling behind Larry Ellison's $117.5 billion.