All special interest groups devote a lot of time and effort studying and explaining themselves. Philatelists write reams about the joys of stamp collecting. Astronomers meet together to discuss canals on Mars, and whether it snows there or not. Computer geeks email each other about why they can't get girl-friends ... no, that's different!

It's partly self-justification, and it's partly self-promotion. But it's also preparation for having to explain what you do and why it interests you to people who don't share, and who perhaps don't (cannot?) understand why you do it.

And by exchanging views in a friendly environment, you get mutual support and perhaps new perspectives that you would never have thought of yourself.

I've said elsewhere that I think the BDSM community is perhaps too self-absorbed and overanalytical, but I acknowledge that the process is a necessary one.