How do you explain the unprecedented success of a trilogy of mommy porn: soft porn aimed at and read by, predominantly, women? In a word: Play. The 50 Shades of Grey books have so far sold 10 million copies in 37 countries. Admittedly, the book's shenanigans could intimidate some couples, but judging by most media reports, the effect has been just the opposite. Women find the books are sparking their libido (the sex scenes are very graphic) and men are loving that.