Hi, welcome : ) I'm new here too.
Regarding the closets...for me, coming out to those I loved about being attracted to all sorts of people, regardless of gender, was liberating and important.
But my poly lifestyle isn't something that I feel comfortable "coming out" about. This is primarily because I feel that it is harder to explain to the society I live in than it is to keep private. I don't go out of my way to hide my family, but it's not something I broadcast either. Not out of embarrassment, but out of a desire to not cause discomfort that I feel is unnecessary. That is to say, I don't think it's anyone's business.
I wonder though, the challenges my children might face as they age. I know that for me, (though I love my family dearly), growing up with an unconventional family structure left me faced with a lot of judgement as a child.