For the past five years, a silent army of video makers have been populating YouTube with clips of themselves playing computer games.

What might once have seemed an unlikely sub-genre has proliferated across the network and been rewarded with its own channel, called Let's Play, or LP. For gamers, it's a chance to combine their video production skills with an innate understanding of the connective power of the internet to create channels dedicated to clips of their game-play.

The goal is not to get laughs, create a viral hit, or even to be competitive; gamers and their subscribers simply love games enough to want to watch other people play. Playing well helps, as does focusing on a popular game – MineCraft channels are particularly popular.

The figures speak for themselves; 24-year old Swedish gamer Felix Kjellberg’s channel, PewDiePie, is the most successful Youtube channel ever with more than 17 million subscribers. He has left One Direction’s channel, with its measly 10 million subscribers, for dust.

But it's not all about the unifying love of gaming. Youtube, which is owned by Google, runs a Partner Program which means that the owner of a video channel can earn a share of the money made from video ads on the site.

One hundred subscribers might not earn a video maker a penny, but 100,000 might buy them a new laptop. And once content attracts a regular audience of more than one million people, those creators become managers of viable, lucrative businesses. Youtube makes no distinction between whether the creator is a seasoned multimedia professional, or an teenager from Hull with editing software and an Xbox.

John Green's mission for AFC Wimbledon

One YouTuber with a dedicated following is John Green, already the successful author behind a string of young adult fiction books. Despite being an American, Green has been using his YouTube channel to sponsor the London football club AFC Wimbledon.

In collaboration with younger brother Hank, Green has a range of educational and vlog-based Youtube channels. Since their first joint channel Brotherhood 2.0 launched in 2007, their enthusiasm and creative range have afforded them legendary status and millions of passionate fans – fans who self-identify as "nerdfighters".

The two also have their own Let's Play channel called Hankgames, which originally featured Hank playing the games Assassin’s Creed and LEGO Harry Potter. But since 2011 it has been dominated by John Green’s efforts at FIFA, a football video game with leagues and clubs that reflect reality but can be customised and "managed" within the world of the game. Despite admitting he is “really bad” at it, tens of thousands watch Green play, coming from his main channel and wider online fan-base.

Ad revenue surpassed five figures

Green has developed a rather endearing persona on Hankgames. While calamitous action unfolds on screen, Green imparts anecdotes, socio-political analysis and the kind of life advice you might expect from his day-job as a best selling author and progressive digital campaigner.

When advertising revenue for this channel passed five figures, it was the potential as a campaign tool that made Green think “something could be done with that money besides buying diapers”.

AFC Wimbledon was founded in 2002 by supporters of Wimbledon FC, a long-established club which was moved from London to Milton Keynes and renamed the MK Dons. By 2011, AFC Wimbledon had played their way through county leagues and conferences to reach League Two, the fourth-highest division overall in English football.

Green does not support AFC Wimbledon – he is a life-long Liverpool fan – but many of his literary protagonists are have-a-go heroes and the nerdfighter community that populates Youtube, Tumblr, Twitter, Etsy and the rest have a strong DIY ethic. So the community-oriented football club struck a chord with Green’s core values.

“Wimbledon had this institution, that was an important part of their community, kind of ripped away from them. And they rebuilt it but it's still very very new. It's a wonderful thing, and one of the great stories in sports in the 21st century, but it is still a new thing. So, anything that we can do to help out with that – we're excited to do it.”

Wimbly Womblys and nerdfighters

Having hit upon the sponsorship idea, he created a new FIFA video game team called the AFC Wimbledon Wimbly Womblys, to star in the Youtube videos that will earn ad revenue relative to how many views they receive. Then he approached the club, who he describes as "initially a little confused". It was hard to explain Youtube ad revenue and nerdfighters to “people running a football club, not spending all their time on the internet".

It helped that he already had solid fundraising credentials. In addition to supporting the microfinancing network Kiva in the developing world, the Green brothers recently formed Subbable, a portal through which viewers can directly support Youtube creators through voluntary subscriptions. It is aimed primarily at education channels, which incur high production costs but might not attract a big enough audience to sustain on ad revenue alone.

Their most ambitious and innovative campaign to date is the Project for Awesome (P4A – the nerdfighter motto and name of Hank’s indie record label is Don’t Forget to be Awesome). For two days in December, anyone could upload a video to Youtube under the P4A banner to promote a charity of their choosing. The drive, established in 2007, has outgrown the nerdfighter community to become a Youtube-wide event. Hundreds of individuals around the world upload videos, usually in the form of a vlog, along with high-profile creators such as Hannah Hart (My Drunk Kitchen) and Charlie McDonnell (charlieissocoollike).

The brothers take it in turns to livestream throughout the drive – on Youtube via Google Hangouts – to motivate donors and feature selected P4A videos. Their aim is also to engage the community in an open discussion of P4A, its purpose and goals, since transparency is another of their key ideals: “I think if you're honest with your audience they will respond much more generously than you would expect.”

In 2012, P4A videos generated $450,000 in donations to the charities they promoted.

The candid familiarity of the entire event is a theme running through the Greens’ Youtube presence and is part of what enables nerdfighters to feel such passion for the community they helped create. It is also what allows Green, he suggests, to partner with a lower-league English football club and convince his mostly American fan-base to throw their substantial enthusiasm behind it, even though, he says “most of them have never seen an actual football game”.

Lively interaction between Green, AFC Wimbledon and the nerdfighter community soon emerged online - in digital ecosystems designed to nurture such unlikely relationships.

“[With] almost every single video that I upload, the real AFC Wimbledon official Youtube channel comments on the game and my terrible play. Nerdfighters love that – they love seeing the real AFC Wimbledon replying to me on Twitter or commenting on the games."

Green invited subscribers to design hoardings, which will go on display at AFC Wimbledon’s ground in the new year, emblazoned with the words: The Nerdfighter Community: Helping AFC Wimbledon get it Wimble-Done!

He is eager to clarify, however, that “we're not sponsoring AFC Wimbledon purely out of charity. We're sponsoring AFC Wimbledon because we care about the club and its mission and we think that it's a cool thing to be associated with".

The sponsorship money is likely to go toward essential kit and helping pay players fair wages. But, as with his Youtube output, Green is particularly focused on young people: “What I'm interested in is youth teams and developing - making sure that football is available to kids. It was a really important part of my childhood."

Despite this being a complicated series of events, the fundamental factor in this story is an abundance of passion - for football but also for online human interaction. Looking to the future, Green says: “I wish more gaming channels would sponsor AFC Wimbledon. I'd like to see them go all the way up to the Premier League just on the strength of ad dollars from organised passionate communities.”

• PewDiePie unseats Miley Cyrus as world's most popular YouTube channel