Explaining 'Fifty Shades' wild success

Story highlights

  • E.L. James' "Fifty Shades" books have sold 31 million copies worldwide since March
  • Insiders say books benefited from perfect storm of smart marketing and e-book mania
  • Some credit trilogy's tame covers with bringing in new audience of erotica readers
  • Hoping to mimic its success, publishers reissue erotica titles minus sensual covers

(CNN)It's a formula that's been tried and tested in countless erotic novels in recent memory.

A rich, handsome man charms a young innocent with lavish gifts and bold declarations of desire. With a smoldering gaze, he melts her insides, turns her legs to jelly and paralyzes her subconscious, paving the way for hot sex scenes while she attempts to crack his steely veneer.
Formulaic as it is, E.L. James' "Fifty Shades of Grey" trilogy is poised to become one of the fastest-selling series in recent years, with 20 million copies sold in the United States and 31 million worldwide since March. Movie rights are spoken for, and in addition to becoming the subject of online parodies, a "Saturday Night Live" sketch, a musical and hotel marketing gimmicks, the S&M-flavored love story of a recent college grad and a billionaire CEO is also credited with boosting sales of sex toys, driving women to hook-up sites and