@CalamityJane,
I'm in the same place as C_Jane. I still post occasionally on topics that interest me, but they are soon overrun by last-worders who can't stop beating the same dead horses over and over again.
Ten years ago I was raising teenagers and actively involved in parenting threads. I think a number of us had kids that were slightly younger than mine and we had lots of ideas to share. We also had a core group who participated in relationships threads. I don't read those any more. It seems that whenever I look in on one it's full of snarky responses - or it seemed that way before I stopped looking at them.
My reasons for being online are social. I work at home with limited social contacts. When A2K became less social and welcoming it became less of a draw for me. I'm not much interested in debates, and I'm definitely not interested in watching last-worders insist on getting the last word.