For me it simply means that if I see someone with that hair color from the back walking I'll probably turn as I pass her to look at her face. However beyond that its about how a girl's face meshes together not something I look for as a trait in a girlfriend. For example I prefer blondes but the most beautiful girl I've seen is brunette... Just checking if anyone else is in the same boat...
It merely means I may find a certain hair color more appealing on a man in general, but it doesn't mean I'll date that guy. At the end of the day, if he's smart, sweet, and good looking, it probably doesn't matter what hair color he has.
And to be honest, for me, it's not a hair color preference. It's the COMBINATION of hair color and eyes: dark hair, and bright blue eyes (good example would be Ian Somerhalder).
So if the guy I'm interested in happens to HAVE that combination, it's like the icing on the cake. Day-um.
I always had a preference for guys with brown or black hair, and green eyes, but the guy I am dating now is blond with brown eyes, and is adorable. It happens a lot that your "Preferences" don't meet reality
I agree with Aercz in this subject. But for me hair color is just something that add a small percentage of attraction to the person in question, in a physical sence. While I don't really compare women to other women, I admit that I'm more drawn to a woman who has red hair, which is pretty much my only stable "preferance" trait on women, though it doesn't affect that much.