I was pondering a bit today on this, and it occurred to me (I doubt this is an thought) that a parenting website is a natural incubator of feminism.
It's rooted in sex. Biology, mostly women's - from TTC/infertility through pregnancy and birth, breastfeeding. And 'gender' - because of which the vast majority of parenting is still 'women's work'. And then, anything which may impact our children's well-being - well, that arouses the tiger in the mildest-mannered mother.
The specific 'parenting' topics we are interested in will likely change over the years along with the ages of our children, but underlying it all is the biological and social realities of womanhood.
I know there are many MNers who aren't parents (or like me, with DC pretty much grown up) - and it's good that this is such an inclusive site. But I don't think any other type of forum could have become such a great place for women and children's rights.