In 2006, 20-year-old NYU dropout Stefani Angelina Germanotta changed her name to Lady Gaga and began her plot to take over the world. It only took about three years. In that time, she brought her Madonna-inspired dance songs from downtown Manhattan's cramped Bitter End to a multiple-night stand at Madison Square Garden. It was easy to dismiss her first big single, "Just Dance," as a pop trifle – but the hits kept coming at a dizzying pace ("Poker Face," "Paparazzi," "Bad Romance," "Edge of Glory"), each one more impressive than the last. Gaga also understands the 24/7 media culture better than any of her peers: she treats the whole world as a stage, posing in outrageously freaky costumes everywhere she goes, from the airport to the Grammys. By preaching the gospel of tolerance and self-respect to her army of "Little Monsters," she's split the difference between Oprah Winfrey and Madonna. It's a highly potent formula that's turned her into arguably the biggest star of the new millennium, with a staggering 34,500,000 Twitter followers. Her only challenge now is finding new ways to wow her audience.