Most have found fame by making videos, which they broadcast on YouTube. Some are motivational speakers whose pearls of wisdom have spread via the Ted Talk channel. Others have done it by taking pictures of their bottoms, and posting them on Instagram.
It is easy to mock this new form of stardom as something flimsy. But this is to forget the long history of celebrities whose column inches rested on no discernible skill - from the previous decade of reality TV stars such as Big Brother's Jade Goody, back to the muses of 60s fashion, such as Edie Sedgwick, and all the way back to Olivia Wyndham, Babe Plunket-Greene and the bright young things of the 20s.
Deyes has three million subscribers to his YouTube channel. PewDiePie, a Swedish vlogger (video blogger) who lives in Britain, has 31 million subscribers.
Then there is Tavi Gevinson, who, at the age of 12, started a fashion blog, and by the age of 15 had her own magazine and was on the front row of New York fashion week alongside Anna Wintour.
Indeed, the "frows" - front rows - at the top catwalk shows in London last week and Milan this week have been filled by bloggers.
These people are not only attracting huge fanbases on the internet, they are making serious money - mostly by taking a cut of the advertising revenue YouTube sells alongside their videos.
Alfie's videos are fun, if pretty insubstantial. A lot are filmed on his phone and feature him larking around in his Brighton flat. Sometimes he does challenges, such as shaving his armpits, making a cake in a cup, or doing yoga in women's exercise kit. But dismissing the phenomenon as transient somewhat misses the point, observers say.
Dr James Bennett, head of media arts at Royal Holloway, University of London, says: "People like PewDiePie, Alfie and Zoella are very skilful at using social media. They are good at telling stories. They are good at creating a new form of intimacy and interaction with fans that is different from the Hollywood studio model of celebrity."
This is the key. Zoella (real name Zoe Sugg, also Alfie's girlfriend) is a beauty blogger and has nearly six million subscribers. She mostly sits on her bed and shares make-up tips, required viewing for any girl trying on mascara for the first time. She is as far removed from an icy fashion model as can be, and, though pretty, she speaks to teenage girls as if they were friends.
Dominic Smales, who represents many of these new stars says: "This sounds a cliche, but they have an x-factor. And that magic ingredient is how relatable they are - how they can connect to millions of people over a tiny screen."
Meanwhile, Alfie dismisses his starry status: "I've never classified myself as a celebrity. The thing about being a YouTuber that I love is that we are normal people. We just happen to be on the other side of the screen. The audience love that we are not reading a script, we're not acting, we haven't got a big camera crew."
Parents should not be surprised that their children have embraced this new generation of internet stars.
Today, those aged 12 to 15 spend more time online (17 hours a week) than they do watching TV (16.6 hours), according to Ofcom, the communications industry regulator.
Some industries have started to salivate at the commercial potential of these stars. Bethany Mota, an American vlogger, has launched her own fashion line, while Zoella will publish a novel later this year.
According to Melissa Cox, head of children's books at Waterstones, this is the first time books have been commissioned on the basis of the blogger's personality. "People really love Alfie and Zoella. They want merchandise related to them."
But for all the excitement about this new breed of celebrities, some suggest it is a case of the emperor clothing himself in a new digital coat.
Mark Borkowski, the public relations chief, says: "Fame is not the same as influence. You need to leverage that fame. Whatever happened to Psy [who sang Gangnam Style]? He had billions of hits.
"Fame ebbs and flows. Will these overnight fabulous nobodies be the Hilary Mantels or Tom Cruises of tomorrow? I doubt it.
