Social-networking sites, like much of the internet, were once a playground for young men. They were drowning in obscure jargon, long rants and, of course, pornography. But nowadays, it is a growing brigade of thirty- and fortysomethings who are behind their extraordinary growth.

Famous users such as Sarah Brown are among those non-teenage women who are increasingly turning to sites such as Facebook and Twitter. New figures show that female users now dominate social-networking sites, and those aged 35 and over are among the fastest-growing demographic for many social networks.

Figures gathered for The Times by Nielsen, the market research firm, show that just over half of all social-networking users in the UK are women. But almost 59 per cent of females “consume the content” of these sites — a jump of almost 10 per cent since last year.

Men may be signed up to social networks, but when it comes to being active on them — talking to other people, organising social engagements and generally taking an interest in other people’s lives — it is women who rule.

Meanwhile, Rapleaf, a “socialmedia-data” company, said recently that worldwide “married women between the ages of 35 and 50 are the fastest-growing segment of social-networking users”. This can be seen in the popularity of Ning, a site that allows users to create their own social networks, whose growth is mainly being driven by women in this age group. Female bloggers and social-network watchers said that the trend makes more sense at closer inspection. They said the popularity of sites such as Twitter was driven by practical reasons, particularly for mothers, who are trying to balance their family duties with their social lives.

“We’re in every night and have a bunch of children to look after,” said Jenny Colgan, 38, the author, blogger and mother of three.

“Twitter is great for while I’m watching something like Strictly or Big Brother. It’s like watching with your friends on the sofa. To go out you’d need a babysitter, or your husband to come back from work.

“We love the sites just because many women are so busy. I can’t see as many of my friends as I’d like to. When I say see, they’re online. I feel more connected to them.”

According to the latest figures from Google Ad Planner, internationally almost two thirds of users on MySpace, the social-networking site owned by News International, parent company of The Times, are women. The majority of users on the site had children in their household. Meanwhile, 57 per cent of Facebook users are women. Many said the way the sites allowed people to keep in touch with friends, through individual messages, “status updates”, and photos, helps people to maintain close friendships with a minimum of fuss.

One female blogger, aged 40, who asked not to be named, said that she held multiple Twitter accounts — one of which was secret so she could talk to her closest friends about the most sensitive of issues.

“One of my friends was going through some really heavy stuff with IVF treatment,” she said. “Through Twitter, four of us talked about it.

“With e-mail you have to wade through so much stuff. [Twitter’s short messages] provided a greater level of control — it felt more direct, immediate and personal.”

Others even argued that women’s hormones, and their more convivial mentality, made them more inclined to take up social networking.

They said that the web was always going to be taken over by women when it became a place to build communities and consolidate friendships.

“Women have a ‘tend and befriend’ mentality,” said Belinda Parmar, 35, the founder of the Ladygeek blog. “It’s due to the hormone oxytocin. Social media is all about connections.

“For men, its about being in a leadership position, competitive advantage. It’s a ‘fight or flight’ mentality down to their levels of testosterone.”

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