Men are on average 33.5% more likely to have internet access than women, according to the Inclusive Internet Index, a survey of 86 countries that are home to 91% of the global population. In some poor, urban areas, men outnumber women online by as much as two to one.
 
To understand why is to see inequalities collide. Globally, women have less access to education and less chance of entering the jobs market, where they will typically earn a quarter less than their male colleagues. It is no surprise that when asked about barriers to being online, not knowing how and not being able to afford it, come up time and again.
 
In Africa, mobile phones drive the growth in internet access, but nowhere is it more expensive to be online. There, a prepaid allocation of 1GB of mobile data a month – enough for just 13 minutes a day on the web – costs on average 10% of monthly earnings. That is 10 times more, as a proportion of income, than a typical OECD citizen pays.
 
To attract customers, telecoms firms in Africa offer deals that bundle in sports TV shows, which are more likely to appeal to men than women.
 
“The man might own the only phone in the house, so the women don’t have access,” says Dhanaraj Thakur, research director at the Web Foundation. According to the Alliance for Affordable Internet, the cost must fall to 2% of monthly income to bring poorer people online.
 
It is not only cost and knowhow that drives the digital gender gap. Women do more unpaid care work than men, and so have less free time. In one survey conducted by the Web Foundation, a common remark from women in 10 developing countries was that going online was simply not worthwhile.
 
Another force at work has its roots in patriarchal societies where technology, and the wider online world, are seen as male preserves. A survey of men in New Delhi, India, and Manila, the Philippines, found that half believed men should be able to restrict what women do online, while two thirds agreed that women should not use the internet in public spaces, such as cybercafes. Such places are dominated by men, but an intimidating atmosphere is not the only deterrent.
 
“When people build cybercafes, there’s a fundamental flaw in design,” says Nanjira Sambuli, a senior policy manager at the Web Foundation. “They assume they are safe places for women to walk to, but often they are not. Then, if they open from nine to five, that doesn’t factor in that women are probably caring for children or trying to do another job. They end up being left behind.”
 
There is also harassment. Misogyny is rife on the internet. A 2014 survey by the Pew Research Center in Washington DC found that a quarter of young women had been the target of online sexual harassment, and more had been stalked online. In Nairobi, Kenya, and Kampala, Uganda, women report extremely high rates of online harassment. The two cities have some of the lowest rates of women online in the world.
 
Some countries do buck the trend. Where men and women are equally likely to go to university, or where women make up the majority of the university population, the digital gender gap is erased or reversed.
 
In Jamaica, more women are online than men – a reflection, perhaps, of the long-standing dominance of women at the University of the West Indies in Kingston.