I have not read 50 Shades of Grey, I have heard that it is awful, but I doubt that it is all that racy. The other option is that my Mother In Law is into stuff that is far more interesting then I give her credit for.
I have not read Harlequin Romances but the romance novels ones that I have read have not been all that racy, and I read the bondage ones. Some of the stuff posted at Literotica is pretty darn pornographic but that stuff is not published.
I do think there is a difference between words and pictures.