Q&A with Joanne Phillips discussion

Hello everyone,
I was on BBC Three Counties radio this morning, talking about the 50 Shades trilogy and why it's been so successful. You can listen here: http://www.bbc.co.uk/i/p00t56zv/ (my bits are at 2:07 and 2:47).
What's interesting, I think, is the way that sites like Goodreads have contributed to the success of this book. My question: Is the main reason for 50 Shades' success its erotic storyline and shock-value? Or is it the social media exposure, and could that work for any book?

I haven't read the trilogy and don't particularly want to, but my theory is that people do like erotic literature and e-readers make it easy to access these kind of books without anyone knowing. And even the paperback versions look like ordinary books, so I think that has been part of the success. And spurred on by the magic of social networking.

Yes, that's a good point about the covers - or lack of on an ereader. It is so much easier to be anonymous about your choice of genre if you have an ereader, especially if you do a lot of your reading in public. I wonder how many people have read this book 'in secret' from their significant others, and I wonder how many of those were men?