They're everywhere.

Asbb-r got onto the subject of adultery. (Discussion of the lives of baseball players, I think was the context.)

Someone made a comment about how "That can't be illegal, can it? I can't imagine." So I cited the Massachusetts General Laws on the subject in response to him. (Hey, it's a Boston Red Sox newsgroup; MGL is probably close enough.)

Another poster responded somewhat irately to the effect of, "And that law hits you whether you're cheating or not!"

I wrote him privately saying, "Uh -- pardon me if this is an intrusive question, but my curiosity has hit me. Are you in a non-traditional relationship of some sort yourself?"

Today the answer came down: Yes.

This makes three or four assbr regulars (counting me) that I know of as being interested in or involved in multi-person or open relationships. (Me, one person who popped up on alt.poly recently, this guy, and someone I'd been in email conversation with a while back who was curious and not sure if he had a personal interest.) It's not something that fits my prejudices of what to expect of the newsgroup, so it pleases me particularly to see counterexamples.