Originally Posted by Darth Cara
I'd also like to mention that it's not always the man with the control. Sometimes the woman will be the dominant one.
Yes, this is a terrible definition. Firstly it's gender exclusive, not sexually exclusive. You can have both male and female doms, and similarly whether the two tie sex into it or not isn't important - either can happen.
Then there's the issue of consent, dominance doesn't come out of some belief that men or women "should" be in control, the relationship is one that satisfies both one partners enjoyment of dominance and the other's submissive tendencies.
Also it doesn't define the term "BDSM" fully. Spelt out, Bondage-Discipline-Submission-SadoMasochism. A BDSM couple can choose to focus on any of the above parts, so ultimately it's up to the individuals to have their own take on what their relationship consists of. Also as Loki. mentioned people assign varied importance to their BDSM identities, some choosing it as their sole identities while others only occasionally taking part in BDSM activities.
Ultimately it's personal choice.