Strangely... no. I don't think it is. Is it empowering for women? Hardly.
EL James's characters in Fifty Shades of Grey were originally based on Bella and Edward from Twilight. I didn't know that when I started reading the book, but when I did find out, it explained a lot. As Twilight was a less than empowering for young women (boy leaves girl, girl tries out different semi-suicidal scenarious to draw his attention), 50 Shades of Grey doesn't inspire much girl power either. Unlike 50 Shades of Grey, the Twilight saga was much better written, however.
Is Fifty Shades of Grey a backward step for people actually interested in experimenting with their sexuality and wanting to know what it's like to play with the darker side of sexual nature? I don't know. But I do know that there are better books on the subject.