There have been numerous threads along the lines of, came for the baby advice, stayed for the Feminism. This is one of the busiest boards on the site, and statistically, I believe, for every poster there are 12 lurkers.
Justine herself has deliberately gone public to say that she favours free speech, which is why she will not bow down to transactivists who deliberately target her revenue in order to shut down the speech that she is trying to platform.
I might have less scepticism over the success of transactivism on her advertisers, if the tide had not already turned in favour of women's rights, with both the Scottish and English government putting reforms on the back burner, legal precedents being set, and many, many people coming out in favour of free speech at universities and penalising those who disallow it. Justine nailed her colours firmly to the free speech mast right when it was unpopular to do it. Many more people have taken the same path, and if anything, she is falling behind the times in terms of openness.
Whatever happens, the optimum time to leverage advertisers has passed.
Mumsnet has at least 12 million unique users. That's a hell of a lot of women, many of whom post and read here.
Hardly a day goes by when I don't read about somebody, often an MP, or journalist, who mentions mumsnet as a source of information or their own. enlightenment.
It's the people who create the content here. That content can happen anywhere.
It's already proven to be massive, huge, unbelievable money maker and source of power.