The digital commons has become a common problem, clogged by disinformation, stripped of privacy and squeezed by insatiable shareholders. Online propagandists stoke violence, data brokers sway elections, and our most intimate personal information is for sale to the highest bidder. Faced with these difficulties, big tech is increasingly turning to Wikipedia for support.

You may not realise how ubiquitous Wikipedia is in your everyday life, but its open, collaboratively-curated data is used across semantic, search and structured data platforms  on the web. Voice assistants such as Siri, Alexa and Google Home source Wikipedia articles for general knowledge questions; Google's knowledge panel features Wikipedia content for snippets and essential facts; Quora contributes to and utilises the Wikidata open data project to connect topics and improve user recommendations.

More recently, YouTube and Facebook have turned to Wikipedia for a new reason: to address their issues around fake news and conspiracy theories. YouTube said that they would begin linking to Wikipedia articles from conspiracy videos, in order to give users additional - often corrective - information about the topic of the video. And Facebook rolled out a feature using Wikipedia's content to give users more information about the publication source of articles appearing in their feeds.

In one sense, we at Wikimedia are happy to see technology companies recognise the value created by Wikipedia's non-commercial, voluntary model. After all, Wikipedia's mission is all about making it possible for everyone to learn and share what they know, and that includes helping people debunk nonsense on the internet. But free knowledge isn't free. Building Wikipedia takes time, labour and resources.

Although critics scoffed when we started 17 years ago, Wikipedia has evolved to become a trusted and beloved resource for the world. The model isn't perfect, but it turns out to work surprisingly well. We get things right most of the time, and when we get things wrong, we keep a list of our failings. We're a work always in progress: studies have shown that Wikipedia articles become more accurate, more neutral, and more thoroughly footnoted as time goes on. We move slow and build things.

But at a deeper level, Wikipedia works because people are generous. Millions of people have contributed their time and effort to create and curate tens of millions of articles simply to share knowledge with the world. And they want that knowledge to be free for everyone. But even the most altruistic creator appreciates a nod for their work and the resources to keep going. Everyone knows the difference between tending a community garden for the use of their neighbours, and tending it for a company to throw a corporate picnic.

According to the Internet Health Report, issued by the Mozilla Foundation (the non-profit that builds the open, privacy-respecting web browser Firefox), "more people are opening their eyes to the real impact the internet has on our societies, economies and personal wellbeing." As a society, we're finally beginning to understand the negative side of our connected society: how much our personal data is exposed, how widely it is used and abused, and the impact that exploitation has on our lives and our societies.

This wasn't the internet in which Wikipedia came of age, and we don't believe it needs to be the internet of our future. Like public parks and free museums, the internet was built as a common resource, on open standards, with an ambition to connect people and share knowledge. But like any commons, it was vulnerable to overuse, exploitation and commodification. If we want to reverse this trend and restore the internet to the public interest, we must act together.

As companies draw on Wikipedia for knowledge - and as a bulwark against bad information - we believe they too have an opportunity to be generous. At Wikimedia, we already love and deeply appreciate the millions of people around the world who make generous charitable contributions because they believe in our values. But we also believe that we deserve lasting, commensurate support from the organisations that derive significant and sustained financial value from our work.

And it's not just us. From groups that set open standards, such as IETF, ICANN and W3C, to organisations that support critical open source projects, such as the Software Freedom Conservancy, to Creative Commons, which enables us to share creativity freely, to the digital knowledge and data commons supported by Wikimedia, we do the work that helps the rest of the internet thrive.

Each of these organisations came into being because they believed that there are parts of the internet that should be in the public interest. Together, they form a sort of "big open" - a collective belief in a commons that is greater when it is open to all. They believed that there are missions that shouldn't have to be subject to quarterly earnings calls. And as such, we have often shied away from placing a dollar (or euro or pound) value on our work.

But this work isn't free. If Wikipedia is being asked to help hold back the ugliest parts of the internet, from conspiracy theories to propaganda, then the commons needs sustained, long-term support - and that support should come from those with the biggest monetary stake in the health of our shared digital networks.

The companies which rely on the standards we develop, the libraries we maintain, and the knowledge we curate should invest back. And they should do so with significant, long-term commitments that are commensurate with our value we create. After all, it's good business: the long-term stability of the commons means we'll be around for continued use for many years to come.

As the non-profits that make the internet possible, we already know how to advocate for our values. We shouldn't be afraid to stand up for our value.

Katherine Maher is executive director of the Wikimedia Foundation