E Jane Dickson: There are better things in life than Mumsnet

Mother's not cross. She's furious. This was the message flashed around cyberspace this week after a nursing mother was ejected from the changing room of a Mind charity shop in East Dulwich. Within hours of the incident, internet parenting forums were calling for a boycott of the mental health charity. There was excited discussion, too, of mobilising Swat teams of lactating mums to stage a mass "milk-in" at the offending shop.

I can't, for the life of me, see why the sight of a mother feeding her child should cause offence. In a world where unfeasibly large breasts jostle for our attention from every shop window, hoarding and newsstand, you'd think we might get over ourselves on the issue of public breastfeeding. I fed two children myself and I don't remember anyone looking twice. Maybe I was lucky. Clearly, the reaction of the Mind shopkeeper, who reportedly sprayed mother and child with air freshener, was exceptionally rude.

On the other hand, the hair-trigger touchiness of self-styled "lactivists" seems a touch hysterical. There is proven worth in lobbying for wider acceptance of a natural function. (Scotland sensibly introduced legislation in 2005, making it an offence to prevent breastfeeding in public places.) Flexing "consumer muscle" also has its place – the boycotting of Nestle in protest at the multinational's aggressive marketing of formula milk in Third World countries has been a notable success – but boycotting a mental health charity because one of its workers is rude makes no sense at all.

I guess you pick your battles. Right now, however, it seems that militant mums are manoeuvring the Maclarens into battle formation on every front. Nowhere is this more apparent than in the phenomenon that is Mumsnet. The "online community" was set up in 2000 by journalist Justine Roberts and TV producer Carrie Longton as a forum where mothers could share views on child-related issues and has smashed through every centile to become a trumpeted political force. This week, Gordon Brown, doubtless still smarting from the drubbing he received when when he failed to disclose his favourite biscuit to concerned Mumsnetters, tipped up up to the organisation's 10th birthday celebrations and pronounced it "one of the Great British institutions".

David Cameron and Nick Clegg, having identified Mumsnet as a bellwether for the middle-class female vote in the forthcoming election, have been equally keen to engage in webchats with its million or so members (You can just imagine the briefings – "It's 'Pampers' sir, not 'Pumpers' and it's a nappy, not a nightclub".)

With an enviable gift for garnering publicity, Mumsnet has put its weight behind important social campaigns – as a body, it pushed hard for the Government's sexualisation of young people review – but you'd never know it from the tone of the online discourse which is numbingly self-interested.

Put bluntly, these are the women you'd fake a fit to avoid at the school gate, kvetching endlessly about "secondary transfer strategy" and the politics of play-dates. (A great many appear to be the mothers of remarkably intelligent children who unaccountably have difficulty finding friends.)

Like any clique, it has its own amusing acronyms; AIBU? stands for "Am I being unreasonable?" and the answer is almost never "Yes. Stop whining". Far and away the most visited topic, however, is the old stand-off between WMs (working mothers) SAHMs (stay at home mothers), with much angsting about "me-time" and how "happy mummies make happy babies".

The development of online communities is routinely hailed as a social revolution but it's hard to see what's revolutionary about this guff; the answer to the work/stay at home dilemma is the same as ever it was: if you have the luxury of choice, you're ahead of the game So FGSGIAR (For God's sake give it a rest). If Mumsnet is the new face of political empowerment for women, I think I'll stick with the old one.

By chance, the 10th birthday of Mumsnet coincides with the centenary of the International Conference for Working Women in Copenhagen, where Clara Zetkin, a true internationalist revolutionary, tabled a proposal for an International Women's Day. Clara may not have been so hot on "me-time", but when it came to political reform and labour rights for women and children, she was smokin'.

International Women's Day falls this Monday and a programme of events is planned across the country. It would be nice if Gordon Brown were to show up at the celebration of the international arm of the TUC, which monitors female and child labour in developing countries. It would be fabulous if he gave his personal endorsement to the march against the murderous practice of female genital mutilation. Then again, dead women – or foreign women – don't vote.

Zetkin and her like understood that while the personal is political, the political need not always be so narrowly personal. Today's "mums' army" could learn from her. Or we can boycott charities and bang on a bit more about biscuits. The choice has always been ours.