It used to be enough for a celebrity to act or sing or swing a bat really well. Now to be considered a real success, he or she needs to sell clothes, hawk fragrances--maybe even invest in technology startups. 
 
 While she hasn’t stormed Silicon Valley just yet, Jennifer Lopez is a state-of-the-art celebrity success story. With $52 million in earnings over the last 12 months and a massive amount of fame, Lopez lands at No. 1 on our Celebrity 100 list for the first time. 
 
 A few years ago it looked like Lopez was done. Her albums, like the all-Spanish Como Ama una Mujer, failed to find the broad audience she once enjoyed. Her movies, like El Cantante, flopped. 
 
 Then in 2010 the singer landed a judge's chair on American Idol. The job gave her a platform to promote her music and turn her image around. It didn’t hurt that she also split from her husband, Marc Anthony. Suddenly a single mother, Lopez lapped up the media attention and scored lucrative endorsement deals with companies like L’Oreal and Gillette. She now has a line of clothing at Kohl's, a top-selling fragrance and she was able to secure a nice bump—to $20 million--on her Idol salary for a second season. With 6.6 million followers on Twitter and 12 million fans on Facebook, she’s also proved a master of social media. 
 
 Lopez unseats Lady Gaga, who topped the list last year. The pop star slides to fifth place this time around with $52 million in earnings, down from $90 million last year (Gaga didn’t tour much in the last 12 months). Her new album, Born This Way, was still a smash hit, selling 1 million copies its first week out. 
 
 Cover Story: Justin Bieber, Venture Capitalist 
 
 In second place is Oprah Winfrey, whom Gaga unseated for No. 1 last year. Winfrey had a rough 12 months. Her 25-year syndication run ended in May but she still managed to earn more than anyone else on the list ($165 million) thanks to her empire of spin-off shows (Dr. Phil, Rachael Ray) her magazine and her radio deal with Sirius XM. Winfrey doesn’t earn any money from the struggling OWN cable network. The talk-show legend will now turn her full attention to trying to improve things at OWN. 
 
 Ranking third: Justin Bieber. Only 18, Bieber is making his second appearance on our list. The star earned $55 million in the past year thanks to touring and record sales, but as he explains in our cover story, Bieber is more than just a pop star. He’s also a budding venture capitalist. Bieber has used his fame and fortune to invest in startup companies like Spotify, Tinychat and Enflick. 
 
 With most of our lists we keep it strictly on the money: earnings or net worth. The Celebrity 100 is a little different. This list--which includes film and television actors, TV personalities, models, athletes, authors, musicians and comedians--is based on money and fame. We define fame as media visibility in print, television, radio and online, plus social media power, which we measure by looking at each celebrity's presence on Facebook and Twitter. The earnings consist of pretax income between May 1, 2011, and May 1, 2012. Management, agent and attorney fees are not deducted. Forbes has been publishing the list annually since 1999. 
 
 Crunching all those numbers always ensures we have an interesting slew of new people on the list; this year, Kim and Khloe Kardashian made the cut. Say what you want about the sisters, they know how to stay famous and earn millions. Thanks to the money she earned from her wedding (and the publicity she earned from her divorce just a few months later), Kim ranks seventh with $18 million. Khloe, who now has her own successful spin-off show (Khloe and Lamar), ranks 73rd with $11 million. 
 
 Another newcomer: Ashton Kutcher. The actor, who took over the lead on Two and a Half Men following Charlie Sheen’s very public meltdown, is now one of the highest-paid men on television. (Sheen failed to make the list this year.) He’s also a savvy tech investor who managed to get in early on companies like Skype, Spotify and Airbnb, which is now worth a reported $1 billion. Kutcher, who is a Twitter superstar, got plenty of press attention this year for his personal life as well as his professional life. He split from his wife of six years, Demi Moore, last fall. The actor debuts in 51st place with $24 million. 
 
 Full List: The Celebrity 100 
 
 Follow me on Twitter at DorothyatForbes. ||||| It's official. It's Lady Gaga's world, and we're simply living in it. She's bigger than Madonna, greater than Angelina. Heck, she's more powerful than Oprah! [Beware of incoming lightning bolt!] 
 
 Forbes placed the singer at the top of its Celebrity 100 list, which ranks the most powerful people in the entertainment business. 
 
 Let’s not quibble too much with Forbes‘ methodology, which credits celebs with the strongest web presence. In this case, they might be confusing simple popularity and crass self-promotion with real power, but let’s move on. Oprah, who earned $290 million in the last 12 months, ranked second, and Justin Bieber debuted on the list in the third spot. No one had a better year than the Biebs in some respects, but he only has to look at the example of Britney Spears, who went from No. 6 in 2010 to completely off this year’s list, to appreciate that people expect greatness every year. 
 
 For the record, Charlie Sheen (28) is winning, at least in his personal grudge match with Two and a Half Men producer Chuck Lorre (77). Angelina Jolie (11) is more powerful than her husband, Brad Pitt (45), and his ex, Jennifer Aniston (21). NFL quarterback Tom Brady (55) edged his wife, Gisele Bundchen (60); and Alex Rodriguez (49) has earned the right to be hand-fed popcorn from his girlfriend, Cameron Diaz (81). 
 
 Overall, it’s an interesting list that will inspire some debate. (Just because she’s done with the Potter series, is there any doubt that J.K. Rowling should have a lifetime pass on this list?) What did you find most surprising? Who belongs on the list, and who’s just a flash in the Celebrity 100 pan? 
 
 Read more: 
 
 Hollywood’s highest-grossing actors of 2010 
 
 Jay-Z tops Forbes list of richest rappers 
 
 Forbes 400: Oprah only 130th richest person in America
– Jennifer Lopez went from superstar to has-been … and has now apparently swung back to superstar. The American Idol judge tops the latest Celebrity 100, Forbes’ annual list of the stars with the most money and fame, with $52 million in earnings over the past year. In addition to her new Idol gig, she’s gotten quite a bit of publicity thanks to her divorce, big endorsement deals, a clothing line and fragrance, and tons of fans and followers on social media. Last year’s No. 1, Lady Gaga, is all the way down in fifth place, while Oprah Winfrey—who was No. 1 the year before Gaga—is No. 2 this year. (But Oprah didn’t make it on Time’s Most Influential People list for the first time ever this year.) Here’s the full top 10, which may make you a little bit sad if you're not 13 years old: Jennifer Lopez Oprah Winfrey Justin Bieber Rihanna Lady Gaga Britney Spears Kim Kardashian Katy Perry Tom Cruise Steven Spielberg See Forbes for all 100.