I just read this book that disproved parts of Dan Brown's "the Da Vinci Code" and I came to a few realizations about the book.  I think the reason why so many people are interested in the DVC is because disproving Christianity would validate their entire way of life.  How rewarding would it be to be able to tell some schmuck who's evangelizing to you that everything he/she believes has been proven to be a lie?  Which means that your way of life has been wrong and mine has been fine.  It's a big "I told you so."

Also, the idea of goddess worship and the sacred feminine is so inherently appealing to our culture of fashionable femininism (much like fashionable liberalism and fashionable homosexuality).  Some stupid guy can read the book and say to some poor unfortunate woman, "Oh yeah I totally believe this stuff about the sacred feminine and how women were written out of Christianity.  I'm on your side."  Stupid.

In my opinion, the bottom line is that Dan Brown is a really smart guy who knows how to capitalize on people's interests.