I'm ignoring the recent discussion about women's equality being evidenced by the existence of women-only swimming sessions at the local Leisure Centre. It's not that I'm not listening - I'm just choosing not to respond.
On another track, what about this for an idea?
It's not so much that you can tell whether a poster is male, female, child-free, enchilded. It's more that Mumsnet has a kind of default setting to a way of being that we might call 'being-with-others'. That kind of mode/stance is quite rare on the internet and in RL public spaces. It's a mode of being that is perhaps associated with parenting. In fact, given the gendered nature of parenting in our present society (though not, perhaps, in our ideal society), it is a mode of being we might associate with mothers.
That is not to say that all mothers are like this, all the time, or that it is a mode of being that is not displayed by others (eg. women without children, men).
However, it is a mode of being that is quite unusual in public life. So unusual that, when male theorists started discussing it, they were seen as revolutionaries in the arena of thought.
Oddly enough, when female theorists have discussed it, and - shock - suggested that it might be associated with mothers, they have tended to be derided and mocked.
Which is kind of interesting.