Friendship is magic is a documentary about a cult following of males that appreciate a show about ponies intended for young girls. It's a pretty good and impartial representation of the genre. You should check it out if you're interested and want a good insider's perspective of the movement.
Sorry about the mean spirited title of the video, this is really the only copy of this I could find on youtube. I should really get vimeo support working on the site. Here is a link to the vimeo video : http://vimeo.com/42481478