It does seem like the majority of us were introduced to MLP:FiM by a friend. It's not the kind of TV show most guys would start watching on our own. I know I fall into that category. Ironically it was someone in the Powerpuff Girls fandom who encouraged me to give MLP a try. I've been a loyal fan for four years now and a forum member for three.
I sometimes wonder though. There has to be some of us who took the initiative to watch MLP on their own. Sure, a friend can learn about MLP from a friend who learned from another friend. But eventually you have to get some original viewers, you know??