How soap operas changed the world
Soap operas aren't often celebrated for contributing to the good of society. Whether it's the materialism of Dallas or the idle gossip of Neighbours, they are better known for being shallow and addictive than for bringing about social change.
But around the world the genre has succeeded in providing "educational entertainment" - a blend of public service messages and melodrama that has enraptured millions of viewers.
Here are some of the things soaps have achieved.
It was in 1951 that BBC radio and the Ministry of Agriculture created The Archers, an "everyday story of country folk", which encouraged farmers to try new techniques to increase productivity in the years after WWII.
"It's one thing to read a persuasive argument in print it's quite another to be persuaded by the power of the human voice," says Andrew Crisell, Professor of Broadcasting Studies at the University of Sunderland in the UK.
"What was challenging was getting the message across without people feeling they are being harangued or preached at."
The series was hugely popular. Still on air 61 years later it is thought to be the longest-running soap opera in the world.
Getting people sewing
In 1969, the rags-to-riches story of a domestic employee who made her fortune through her skills with a sewing machine provided the template for an entertainment education revolution.
Simplemente Maria, a Peruvian TV telenovela - a soap format with a limited run - was extremely popular throughout Latin America and led to a rapid increase in both sales of sewing machines and people enrolling in sewing classes.
Simplemente Maria was especially popular in Mexico, where it was rumoured to have received higher viewing figures than the 1970 World Cup.
Teaching adults to read
Mexican television writer Miguel Sabido began studying the Simplemente Maria phenomenon. He had written several popular soaps for a major Mexican broadcaster but was frustrated with the vacuous content. He drew up a methodology that writers could use to create drama series that would be both popular and educational.
In 1975, half of Mexico's workforce was illiterate and though the government had initiated a public adult literacy programme, it had a low take up. Sabido created a series called Ven Conmigo, in which an elderly man graduated from literacy class and in an emotional scene read a letter from his daughter for the first time.
An epilogue to the episode mentioned the national distribution centre that provided free literacy booklets - 250,000 people showed up the next day to get their copies, and enrolment in the government programme increased nine-fold over the course of a year.
Marriage for love
In 1984, Sabido was invited to India by Prime Minister Indira Gandhi to work on the first serial drama series on the subcontinent. He created Hum Log, a series that took on big issues such as caste harmony and empowerment of women - and drew a regular viewing audience of more than 50 million.
One of the characters, a girl from a Hindu family, falls in love with a Muslim detective, and another wants to marry a woman from a lower caste.
"Anyone over the age of 20 will know Hum Log," says Sean Southey, director of PCI Media Impact, the US-based organisation that worked with Sabido on the series.
"In those six or eight characters you had a set of new Indian values… a different approach to caste, eliminating the idea of Untouchables. This was a bold and beautiful vision of what India could be."
Each episode concluded with a message from the famous actor Ashok Kumar, who encouraged viewers to discuss issues raised in the programme. Over its 17-month run, he received more than 400,000 letters from young viewers, pleading with him to convince their parents to let them marry the man or woman of their choice.
But poor people didn't own television sets, so PCI Media Impact soon realised it could reach more people through radio. In 2002 it created a radio drama called Taru, set in the Indian state of Bihar, which challenged the preferential treatment of boys over girls.
The series' researchers found that girls in rural Bihar didn't celebrate their birthdays and decided to tell the story of a plucky young girl who petitions her family to throw her a party - and wins them over. Listeners across the region followed avidly as a little girl planned her birthday party for the first time.
In his follow-up research, Arvind Singhal, professor of communication at the University of Texas at el Paso, saw birthday celebrations for girls popping up around the region.
"It had the elements of an infection," he says.
In 1989, the British soap Eastenders aired the first gay kiss on British television, prompting one British newspaper to run the headline "Filth! Get This Off Our Screens". Actor Michael Cashman received a brick through his window.
"On the second kiss there was barely any fuss. By the third kiss barely anyone noticed," Cashman wrote in The Mirror newspaper.
Another first occurred in 2007 in Vanuatu and Fiji, when a gay character appeared on screens in a series called Love Patrol. It has since been aired on TV in other Pacific Islands - a region where homosexuality is profoundly stigmatised.
"People are saying we actually do have gay men in our community too and they have rights," says Robyn Drysdale at the University of New South Wales, who has studied the reaction.
"There is a lot of discussion going on around human rights, and respect and an increased understanding of quite marginalised populations. That hadn't happened before."
A number of soaps in East Africa have challenged taboos by discussing sexual health issues.
A series in Sudan told of the agony of a girl who underwent female genital mutilation, and the problems it created for her. Between 2004 and 2006, when the programme was on air, polls suggested growing opposition to the practice.
"We present these issues in a safe environment, not judging or condemning the people who have practised it but drawing attention to the fact that it can create harm for people they care about," says Katie Elmore of Population Media Centre, which made the series.
A youth-focused radio series in Ethiopia, between 2002 and 2004, led to an increase in demand for contraception. After Dhimbibba went to air, an independent poll found that roughly a quarter of those seeking contraceptive advice at 48 health centres had been inspired by the series to visit the clinic.
In 1994, when the Taliban were in power in Afghanistan, a team from the BBC created a radio drama that promoted women's rights and told listeners how to avoid the danger from landmines, which littered the country.
According to research by the UN, those who listened to New Home, New Life regularly were half as likely to be killed by a landmine.
"Hardliners within the Taliban were concerned and obsessed about the series," says Gordon Adam, one of the programme's producers.
"They discussed banning the programme. Of course, it would have been impossible to enforce, as so many of the Talibs themselves were listening to it and enjoying it."
Soap operas are used by the BBC's international development charity BBC Media Action to help people around the world access information.