Book excerpt: Famous for her avant-garde outfits, over-the-top performances, and addictive dance beats, Lady Gaga is one of the most successful pop musicians of all time. But behind her showmanship lies another achievement: her wildly successful strategy for attracting and keeping insanely loyal fans. She's one of the most popular social media voices in the world with more than 33 million Twitter followers and 55 million Facebook fans. And she got there by methodically building a grassroots base of what she calls her "Little Monsters" - passionate fans who look to her not just for music but also for joy, inspiration, and a sense of community.