I agree with Tom, but I think there is also more to it than that.

A well-known dom blogger has a theory that I think makes a lot of sense. She thinks that more women would enjoy being dominant if they didn't have such a strong cultural association between "dominant woman" and "a tall, thin, Barbie-type woman in uncomfortable PVC clothes and six-inch heels, waving a bullwhip in the air." The pop-culture idea of the "dominatrix" is a male fantasy, not a female one, so most naturally dominant women aren't really turned on by the idea of becoming that fantasy. Just like the gay person who spends years thinking "but I can't be gay! I don't act gay!", the dominant woman might take a long time to realize that the urge to dominate a partner is not one and the same with the urge to wear thigh-high stiletto boots.

Also, subservient, I'm not sure exactly what you're looking for, but I'm a woman who enjoys dominating other women (okay, I'm bi and a switch, so I can pretty much pinch-hit in any emergency ). I also spend way too much time futzing around online. So send me a PM if you want to chat anytime.