Oprah is once again Forbes' most powerful celebrity after slipping to No. 2 last year on the annual Celebrity 100 list. Last year's No. 1, Angelina Jolie, fell all the way to No. 18, while Beyonce shot up to No. 2. To determine the rankings, Forbes looks at 12 months of entertainment-related earnings; media visibility in print, on TV, on radio and online; and social media presence, a new measure this year. Here's a quick look at the top 10. Find the full Forbes list here.