The phrase philanthro-capitalism gives me the heebie-jeebies. It conjures up an image of hedgefunders and CEOs who could never have got that rich in the first place other than by fostering iniquity then having the brass neck to recast themselves as the healers of that iniquity by sprinkling down the surfeit of their superflux.

But this is the ninth year of the Skoll World Forum in Oxford, where social entrepreneurs meet huge money, where the leaders of the largest businesses on earth talk about whether or not capitalism is "sustainable".

Jeff Skoll was the first employee and first president of Ebay. Nobody could say he got rich off iniquity – off "peer-to-peer" purchases you sometimes kicked yourself over, maybe, but not iniquity. He's worth $2.9 billion, which puts him at 401 in the Forbes world rich list.

The Skoll Foundation radiates good works: besides this forum, there are awards and grants to projects all over the world that have saved and changed people's lives; there are scholarships for MBA students at the Said Business School in Oxford. Skoll distils this North American philanthropic model (he's actually Canadian) – the emphasis on dynamism more than altruism, the horizons huge.

Anyway, look, charity is dead – everybody says so. You overhear it walking past chino-ed young men pronouncing NGO as if it's a dirty word, and "government" as if it's a punchline to some sick joke. Victor d'Allant, the executive director of Social Edge, said "it's all about social entrepreneurship versus charity. Nobody wants to do charity anymore. Charity doesn't work".

I met him on the coach to Oxford – I thought if there was anybody left in the world who still believed in charity, it would be people who liked coaches. We'll do the autopsy on charity in a minute. Firstly, though, what replaces it? If it's not philanthro-capitalism, is it social entrepreneurship? If it's not social entrepreneurship, is it impact investment? What do these phrases even mean?

Andrea Coleman founded Riders for Health, which operates out of seven African countries, getting reliable healthcare to women who need it in remote areas. Their health workers started out on motorbikes (Coleman and her husband, Barry, were big in the motorcycle racing scene – he actually used to report on it for the Guardian) and about a quarter of their funding is still raised at bike events, even while their African project now includes a lot of jeeps.

"I knew I didn't want to go out and shake a can. And I knew that donor culture is no good for the recipients, it just trains Africans to be donor-dependent. But in the UK, a lot of people are wedded to a very Victorian idea of philanthropy. We've had terrible trouble with our board, they don't believe you should ever charge because donors should be donors. So when we were looking for support, we found it mostly from America."

So what does this actually mean? Firstly, that Riders for Health would in many cases be paid by the relevant department of health; so they wouldn't be a charity, they'd be a service commissioned by a government. Secondly, if they want to use the financial system, they can – they've got a project in the Gambia where they raised $3.5m for a fleet of medical vehicles.

The money was lent by a Nigerian bank, underwritten by the Skoll Foundation, the interest is paid by the Gambians and Riders for Health creates a life-saving infrastructure. That's social enterprise at its most appealing: "I love the idea of charity, I want to help. But you've got to bring into that picture empowerment and permanence. You can't build a future on the unpredictibility of donation".

But in the same vein is "impact investment", where high-net worth individuals (this, amusingly, is what rich people like to be called) will plough money into a project having been told that it's beneficial – environmentally or socially – and will then want to see results. Even if that's a "triple bottom line" (a business that is that's two-thirds money and one third responsibility), that's still a lot of pressure on a project that might only be one footfall out of chaos.

Eve Ensler, the playwright, was persuasive on the subject: "The idea that you think, because you're giving them money, they have to prove something to you, why? If you get to give out money, get down on your knees and thank the good goddesses that you are so fortunate. Don't expect people to treat you like you're god, because you're not."

The complex ethics of the donor/recipient relationship (What should have strings attached? What should the strings look like? Who should pull them?) is unwieldy even to describe by this muddle of a string metaphor.

And that's before you even consider the more obvious controversies, such as the Jita project in Bangladesh, where women are fronted supplies to sell to one another. It's great. "Part of life's transformation," said Nick Southern, Jita's chairman, "is can you move? In a very poor society, mobility, self-confidence, some disposable income, these things are transformative."

Then they make great choices, they send their kids to school, they buy a boat for their husband. And yet, at the same time, are these products servicing real needs, or is this just a new market being manufactured for Unilever? One of the products they sell is Fair'n'Lovely, a skin-lightening cream. To the poorest people on earth, whose skin looks great. Is this social enterprise or a Trojan horse for needless stuff?

This is frontier territory: some of it is bound to look a bit ugly, and some of it will look like the future. Seth Tabatznik, who runs Berti Investments and is scion of the pharmaceutical fortune that was previously Arrow Generic, said "You can spend your whole life interpreting the world, but until you actually get out and do something, you can't complain about it."