e.b., csr, nibbles, I think you have brought up a very important point here. Thank you all!!
Sexual and relationship interests come in various flavours, degrees, nuances. You mention the dominant - switch - submissive continuum, and the straight - bi - gay continuum. There might even be other spectra with reference to sexuality?
Another thing that comes to mind is that one's position on the DS continuum can change in the course of some people's lives. As ValKyrie describes with her journey from switch to dominant. And that it can change depending on with whom one is interacting: whenever there are more than two individuals in the picture, we enter the realm of complex hierarchies. As described, for example, by women who interact submissively with a male dominant, and dominate another woman / other women.
Sometimes I wish that people engaged in sexual discovery would not feel so pressed to choose a fixed sexual 'identity': 'What am I really?' What's wrong with allowing oneself time to experiment? What's wrong with being open for surprises in the course of one's life? How about wondering a little less about being something, and try out doing something?
Also, should there be members on this forum who have not filled in their profile because they are not sure... I hope they read your comments in this thread and give themselves a break. Finding out that one is interested in BDSM does not necessarily and automatically mean that one already knows which role one would prefer (if any). What's wrong with leaving the 'BDSM Role' part blank, or write 'don't know' ? I am sure everyone here welcomes posts from people who can't really tell where on the continuum they currently reside.