In the United States online crowdfunding has been called the "sad, dark future of healthcare". But what does it mean in Australia, where the public system is meant to stop people falling through the cracks?

On GoFundMe, one of the internet's largest crowdfunding platforms, Australians have raised more than $145 million for personal causes. Even chief executive Rob Solomon is surprised that here, just like in the US, medical campaigning is the most popular category.

Users often disclose their most intimate moments in an attempt to capture the empathy of people scrolling by. It can be hard to know where to stop.

One day you might ask for followers on Facebook. The next you might ask for the help that will save your life.

Government records show that in 2016-17, ill health was the primary cause of non-business-related personal insolvency for 1,830 Australians.

But more than any statistic, crowdfunding webpages show how easily an accident or illness can push a once secure life to the edge, even with universal healthcare.

Trisha Cashmere's son Angus was diagnosed with Hodgkin's lymphoma at age 10. The family turned to crowdfunding after the cancer returned in 2015 and the drug he needed was not available to certain relapsed patients though the Pharmaceutical Benefits Scheme (PBS).

The family estimated they would need about $180,000 to purchase the required doses, illustrating some of the financial challenges facing those with rare cancers, which have historically been underfunded.

Ms Cashmere used Rare Cancers Australia's crowdfunding site and the campaign was extraordinarily successful. The family raised $264,036 — more than double their goal — and shows such as A Current Affair covered Angus's story.

After the media exposure he was accepted onto a patient access scheme, bringing the price down to about $80,000. With the family's blessing, excess funds were given to several other rare cancer patients.

Who gets help?

Reflecting on her experience after those years of publicity, Ms Cashmere observed that when adults get sick, people inadvertently try to attribute blame — "what did they do to cause it?" — especially for conditions like lung or bowel cancer.

For kids with cancer, it's different.

"With children it's very difficult to see what they could possibly have done," she said. "It makes children very sympathetic, so it makes people generous."

Ms Cashmere is thankful people felt moved to support her son, but she cannot help but feel for other people who might be older or have chronic illnesses.

They might be asking themselves "If only I was a little bit cuter, a little more telegenic".

Research suggests some people do better on crowdfunding platforms than others. ( ABC News: Humyara Mahbub )

It's a crowded marketplace. And, as reported in a Financial Times investigation of American crowdfunding, "not every product finds a market."

Certain narratives have become popular ways to signify why particular patients deserve help.

"The idea of a brave child … or the male breadwinner who has been struck down by an early onset case of cancer — these are dominant tropes," Nora Kenworthy, an assistant professor at the University of Washington Bothell, said.

There is little Australian research about who crowdfunding works for, but Dr Kenworthy found in her study that US campaigners with a single, significant medical crisis were often more successful.

It is simply an easier story to tell.

"They are also able to articulate it as a sort of solvable problem," she explained. "'If you give me money right now, things will get better for me'."

Meanwhile, if someone had multiple or chronic health and social crises stemming from poverty, for example, it might be more difficult to tell a compelling and viral story.

"By virtue of being more needy, they may appear less deserving," the study states.

Richard Vines, the co-founder of Rare Cancers Australia, has seen these dynamics.

"There are inevitably people who don't do well," he said. "I think sometimes stories catch fire and, to be fair, the story of a child with cancer will always catch fire."

The system is not perfect

Australians are justifiably proud of the country's public healthcare system, but doctors are concerned that rising out-of-pocket costs keep people from filling prescriptions or seeing specialists.

In 2015-16, individuals contributed about 17 per cent of total health expenditure.

Even with private insurance, it is hard to reckon with the full financial burden of stage four cancer. For some, that is where online crowdfunding can make up the difference.

In 2016 high school teacher Yasmin Remynse was diagnosed with a rare primary cancer of the appendix, along with secondary cancer elsewhere in her abdomen.

She can no longer work and the disease has spread to her lungs, meaning she needs at-home oxygen.

Her students started a GoFundMe page, and another friend launched a campaign on Rare Cancers Australia's website, which runs its own crowdfunding platform.

They have so far raised $6,000 and $2,205 respectively, and Ms Remynse is grateful for both.

"We've had to rent out the house, move into my parent's house with them just to financially manage," she said.

"The cost of medication, the cost of my husband having to stay in accommodation near where I was in surgery because it was too far to commute… It [the money] has all come in handy. We'd be lost without it."

It can be a hard choice for parents to crowdfund care for their children. ( ABC News: Humyara Mahbub )

Why some succeed

Asking for help was hard for Ms Remynse, and she also had misgivings about what she called the "popularity contest" of raising money for medical care.

Crucially, successful crowdfunding requires users to become expert marketers, broadcasting consumable images and illness details to an audience.

GoFundMe, for example, does not hide the sell. It advises users to write a "catchy title" or write a "captivating story".

Mr Solomon calls his website a "storytelling platform".

"Pictures are worth a thousand words. If you can shoot a video, it's maybe worth 10,000 words," he said.

Jeremy Snyder, an associate professor at Simon Fraser University who has studied crowdfunding, suggested this exchange could be particularly difficult for parents.

They may post medical information online that could form a permanent record of their ill child's life. But in a crisis, what wouldn't you do?

For the Cashmere family, sharing Angus's story with the public was not easy. "Certainly for Angus, as a teenager, it was a very tricky thing for him to navigate," Ms Cashmere said.

The trade off is still one she is satisfied with, however. By sharing their story, she feels it made a difference for people with rare cancers.

"When it's you in the situation, you just want to do everything you can to be better or live longer or to have a better quality of life," Ms Cashmere said. "It's a very difficult moral landscape."

But, as a society, we should be concerned crowdfunding is on the rise, Dr Snyder warned.