What do you need to run a TV channel? Not much these days - get a cheap video camera and access to the internet, and you can soon be a TV tycoon, albeit on a very small scale. But I've been meeting two channels run by young British entrepreneurs who are showing the TV establishment the way to connect audiences and grow businesses in a hurry.
The first is 21-year-old Jamal Edwards. He grew up on a west London housing estate and left school with few qualifications, but he now has a business called SB.TV, offering all sorts of original video content on YouTube and making some serious money from it.
When I popped into his recently acquired offices in Ladbroke Grove, where three of his staff were hard at work, he told me how it got started:
"When I was 14 or 15, I got a video camera for Christmas and I started going out on my estate and filming lots of rappers - and from there it snowballed. I just kept filming every day."
While working by day in a clothes shop, by night he taught himself about making videos and running a business by watching online tutorials. Eventually a cheque arrived from YouTube for the revenue from adverts placed around his videos. "I thought yeah I can give up working at Topman and make it a business."
The channel has had over 100 million views, and Jamal is very proud that every bit of the content has been filmed by his team. Some artists that have been featured on SB.TV from Jessie J to Ed Sheeran have seen their profiles boosted - for others it's been the only way to get their music to an audience. Jamal says the key for his business is to build a community, and respond to what its members want.
Google has already featured Jamal Edwards in an advert, and mainstream TV and music firms are watching SB.TV very closely, desperate to understand the connection it has with its audience.
I would not be surprised to see an approach from a potential buyer, but Jamal says he's just concentrating on growing his channel: "I'm just trying to think of new fresh ideas, keep it buzzing. It's gonna go worldwide man!" he told me. "Music, fashion, sport comedy, just gonna build it up."
Unless you're a teenage gamer, you may never have heard of Yogscast, but it is an even bigger video phenomenon than SB.TV. Much bigger, in fact, with one billion views to its YouTube channel so far, and three million people tuning in each day.
I first spotted it when browsing through the "most viewed" section on YouTube. It seems to be packed with videos about games, all of them accompanied by a slightly eccentric commentary by two young men.
"That's Simon and Lewis from Yogscast, dad," my teenage online game-obsessed son explained, in a voice which suggested that anyone who hadn't heard of them must have been asleep for 100 years.
So I went to meet Lewis Brindley and Simon Lane in their shiny new offices in Bristol, global headquarters of a business which has only recently moved out of their respective bedrooms.
Lewis was working as a freelance journalist four years ago and played online games with a group of people including Simon. "We would all group together to kill virtual dragons."
He decided that the entertaining chat that happened during the games needed to be put online, so he started making videos featuring him and Simon - who he hadn't even met in real life at that stage.
Their double act soon proved popular, especially when they began to focus on Minecraft, a creative game which allows players to build their own worlds and adventures. Then came a key moment: "I woke up on Christmas Day in 2010 and we were the most viewed video on YouTube," Lewis explained. "That was when it hit me that this was maybe worth quitting our jobs for and having a good go at it."
They have certainly had a good go. Yogscast has assembled a team of more than a dozen people who can all make and edit videos in their new studios in Bristol. Every day, they upload at least one video, with an average length of 15 minutes, and they are working on improving the production values. "If you don't produce good quality videos, then people won't come back," says Lewis. "We listen very carefully to what our community says."
They are building a network of people making similar videos, and there is an exciting new project, their own video game. Using the crowdfunding site Kickstarter they have raised over $500,000 to create Yogventures, in collaboration with a Los Angeles based game developer. It sounds rather like Minecraft, and if it succeeds on that scale when it launches next year, then Yogscast will be a serious player in the games world as well as in online video.
So what are their ambitions? "I want to be the next Rupert Murdoch," Simon told me - though I'm not entirely clear how serious he was. But Lewis, the straight man in the comedy duo, seems pretty focussed on expanding Yogscast and making increasingly professional video content.
But has either of these businesses really got a chance to make an impact on TV? When I spoke to the respected media analyst Theresa Wise she freely admitted she'd never heard of either of them - but was impressed by what I told her about their ambitions.
She warned, however, that this was a hits-driven business: "There are two issues - keeping generating the hits and convincing people you're still cool. When dads start to like you there's a danger that people switch to other things."
It is, in her words, a "fickle old business". But wouldn't it be great to see Jamal Edwards and the Yogscast duo Simon and Lewis prove that in the internet age Britain can create TV tycoons with staying power?