 Jeff Bezos of Amazon, Mark Zuckerberg of Facebook and Michael Bloomberg of Bloomberg L.P., appeared for the first time on the "Forbes" top 10 billionaires list, coming at fifth, sixth and eighth positions, respectively.Zuckerberg became the youngest top 10 billionaire this year at the age of 31.Larry Ellison, Charles Koch and David Koch also slipped from their previous year's positions, with Ellison dropping to seventh from fifth, and the Kochs falling to ninth position from sixth.