Clare Short never managed it and Germaine Greer changed her mind about even wanting to, but now a woman with 23 followers on Twitter seems to have pulled off something of a feminist coup by getting Rupert Murdoch to publicly criticise the Sun's Page 3.

It was an ordinary Sunday afternoon when Karen Mason, using her nickname to tweet as @Kazipooh, decided to vent her feelings about the daily diet of topless women in Britain's biggest-selling tabloid newspaper to the man in charge. Addressing @rupertmurdoch (followers: 406,217) she wrote: "Seriously, we are all so over page 3 – it is so last century! #nomorepage3".

His response, less than an hour later, read: 'You maybe [sic] right, don't know but considering. Perhaps halfway house with glamorous fashionistas."

Within a few hours this public recognition that the head of News Corp was at least considering an end to something called a "British institution" by the Sun's editor less than a year ago had been retweeted more than 200 times.

No More Page 3, the campaign launched in response to the dearth of sportswomen in our tabloids after the London Olympics, was over the moon. Laura Ashton, one of the campaign's volunteers, said: "This is really encouraging. It's the first time we've had a proper response from somebody at the top." @NoMorePage3 tweeted: "We are doing this! @rupertmurdoch is listening!!! Is there anyone with you who hasn't signed [the petition]?"

The "Take the Bare Boobs Out of the Sun" petition on online site Change.org has more than 64,000 signatures including those of Jennifer Saunders, Alistair Campbell and Lauren Laverne. Another of them is that of Karen Mason, whose online presence is dominated by a picture of a little black-and-white dog and the fact that she "would rather have a bottle in front of me than a frontal lobotomy".

Speaking from her home on England's south coast, Mason said she had tweeted Murdoch in response to the campaign's request that she did. "Nobody was more surprised than me, to be honest," she said of the billionaire's decision to answer.

Mason's Twitter feed is largely restricted to moans about the kids making the hallway walls grubby or walking the dog. But the mother of two teenage daughters is a supporter of No More Page 3 as well as the One Billion Rising campaign to end violence against women and girls. "I am just pretty fed up with the casual sexism that goes on in society. It is slowly becoming more and more hypersexualised, which is a real problem for young girls," she told the Guardian.

In answer to one Sun reader who suggested she simply read something else because young girls wanted to appear topless, she retorted: "That's the problem really, isn't it? Girls sense that that is what they should aim for."

Page 3 has survived since its launch in 1970 through a powerful combination of economic argument (credited with boosting sales fourfold after launch) and the defence that it was "just harmless fun". With much more pornographic, violent images available elsewhere, where's the harm? Some senior newspaper editors have even suggested to me that removing it would be a denial of freedom of expression, presumably for any young woman who wants readers to ogle her breasts.

In a coup of sorts, the Sun even persuaded Germaine Greer to celebrate its 40th anniversary by claiming that these "glamour" shots were lovely and served to "cheer her oddjob man up".

Yet research shows that, across the media, men are typically photographed going about their business – whether in suits or sporting attire – while women are most typically shown looking pretty or near naked. In research by Women in Journalism at the end of last year, only three females made the top 10 of people pictured on national newspaper front pages – Kate Middleton, her sister Pippa and Madeleine McCann. In terms of role models, marrying well or being victim to a terrible crime seems to be the best way to be noticed.

Mason says she was inspired to act when she compared her own early teen reading – "there were lots of ponies" – with that of her daughters: "There are magazines that explain how to perform sexual acts." Given this hypersexualisation, Page 3 is "symbolic of a much bigger problem". "If it was to be toppled it would make a huge difference."

Several hours after his response, Mason responded to Murdoch's suggestion by tweeting: "Glamorous fashionistas? Boring! Go for broke and feature independent, interesting, relevant women from all walks of life?"

Following Murdoch's tweet, hundreds of people started to suggest alternatives to naked breasts for the Sun. A sports section for female athletes? A page to celebrate heroes in the armed forces "men and women"?

Appearing for all the world as though the off-duty quips of the uber-boss had taken them by surprise, News Corp yesterday said it had "no comment" about Page 3's long-term future. Insiders cautioned against reading too much into his comments although admitted that Murdoch's recent use of Twitter to contradict the public statements of his editors (he did the same to the Sunday Times over Gerald Scarfe) was causing some difficulty.

In his second appearance before the Leveson inquiry, Dominic Mohan, the Sun's editor, had argued that the daily photograph of a topless woman was "meant to represent youth and freshness" and "celebrate natural beauty".

He admitted, however, that he would never have trashed the Labour politician Clare Short in such a vicious way if she were to campaign against Page 3 now, as she did in the 1980s. At that time, she was derided as "fat" and "jealous" when she dared to suggest that putting topless women in a family newspaper sent the wrong message.

Today, of course, campaigning looks very different. Lucy Anne Holmes is a writer and actor who decided to launch No More Page 3 with a website and petition because "she became sad that the most prominent (excuse the pun) photograph of a woman in the widest circulation British newspaper is of a young woman in just her knickers".

Murdoch was reported to have been unhappy with the launch of Page 3 but was persuaded by the sales success of a paper that really was "super soaraway" in its early days. Like most of the industry, that success is now muted, with sales of 2.4m copies a day in January, down more than 12% year on year. Murdoch may have decided that Page 3's future is online only. The topless pictures are not easily found on the front page of thesun.co.uk. They appear on a successful standalone website, www.page3.com.

The internet has been blamed for increasingly violent and easily available pornography and as a channel for misogynistic abuse. But it has also helped feminist causes. Witness the 20,000 women who have contacted Everyday Sexism with daily examples of unpleasant behaviour.

Now in her 50s, Mason joined Twitter in February 2009 and produced just four tweets until last year when she started adding campaign tweets to her usual fare. One of her earlier tweets read: "Crikey – I am sure must be a huge disappointment to anyone following me as this is still a mystery to me and don't log on enough …" Few campaigners are disappointed today.