The rise of the tweenage vlogger

Nikki Christou, 12, known in the vlogging world as Nikki Lilly, makes YouTube videos about baking, make-up and a rare medical condition known as arterial venous malformation (AVM), something she was diagnosed with when she was six.

Her condition has resulted in a severe facial disfigurement and the constant risk of life-threatening nosebleeds.

She doesn't get many "haters" on her channel but admits that when she began vlogging, the cruel comments did upset her.

"It definitely got to me at first, and I may have shed a few tears - but, as I've grown as a vlogger, I've learnt that the comments from the haters are basically all the same.

"They may say things like, 'You are ugly,' but really they don't like themselves and they have nothing better to do."

Nikki currently has more than 200,000 subscribers to her channel and hopes to break the million mark at some point.

Making videos started as a hobby, a natural follow-on from the role-playing games she already loved.

When she began posting them to YouTube in 2013, she became part of a new generation of tweenagers - children from eight to 13 - who run their own channels.

She advises any newbies to "make sure they always show what they have made to their parents".

At first, Nikki's parents, worried by the reaction she might receive, insisted that the comments section was turned off.

But her mother says that once they saw how much it meant to Nikki and how much she craved feedback, they changed their minds.

Shauna Pomerantz, associate professor at the department of child and youth studies at Brock University in Ontario, Canada, says Nikki is a great role model for young girls.

"She is the champion of the not-perfect girl, and she is absolutely inspirational to watch," she told the BBC.

"I can see why people love her - she is a hero to anyone who feels like an outsider."

Across the pond, 13-year-old American dancer and singer JoJo Siwa vlogs about much the same thing as Nikki Lilly, although, with more than three million followers, she is better established.

There are, says Prof Pomerantz, thousands of similar girls on YouTube and they are "mostly white, upper-class, pretty and thin".

Prof Pomerantz's own nine-year-old daughter is a mega-fan of JoJo's, and while her daughter doesn't know why she likes her so much, her mother thinks there are two main reasons.

"Firstly, this is a world where no adults are visible and it is fantastic for children to see a world where kids are in charge."

The second reason is likely to be the normalcy of the videos.

"This stuff is really very mundane," Prof Pomerantz says.

"Any adult watching would be bored within seconds.

"These vloggers invite their fans on closet tours, show them how to do a high ponytail, show them their underwear."

And this means children can relate to these "stars" in ways a previous generation could not, says Prof Pomerantz.

Gone are the days when celebrities were one step removed, in the pages of a glossy magazine or on the set of a TV programme - now children are quite literally invited to look around their bedrooms.

Nikki Lilly is a huge fan of Zoella, who, at the grand old age of 27, is a veteran of the beauty vlog.

She says she loves her because "she is like a chatty girl next door".

But Zoella, like other celebrity vloggers, has another secret to her success, a willingness to share her vulnerability with her fans - in her case, crippling anxiety.

Much has been written about how the YouTube generation are growing up with no privacy - willing to share on social media every detail of their lives, but Prof Pomerantz is not overly concerned.

"While their mothers may have kept a diary under lock and key, now there is a different way of sharing secrets and young people are happy to tell the world," she says.

"In some ways, this is a form of empowerment.

"Young people are more likely to be open and honest."

Journalist Zoe Williams worries, though, that YouTube could be spawning a generation of egotists.

Writing about Zoella in the Guardian newspaper, she says: "Her delight in the inconsequential is perversely infectious; there is something rather relaxing about the company of a person who will say out loud anything that pops into their head."

But, she adds: "The depth of her fascination with herself is also rather alienating."

There is no shortage of children desperate to mimic their YouTube heroes and start their own vlogs - but, for the vast majority, stardom is unlikely to follow.

Amanda Lenhart, a senior research scientist at the NORC Center for Public Affairs Research, says for those who do not get many followers, it is simply a valuable life lesson.

"It is not pleasant, but is it any different from wanting to be a professional football player and finding you are not good enough? It is part of growing up," she says.

Justin Escalona, 20, who started a YouTube channel with his friends when he was 11, has some advice for children wanting to do the same.

"I think having an outlet for young kids to express their creativity is a positive thing," he says.

"Just don't put stupid or inappropriate stuff online and don't worry about getting views."

Now a film student, his vlogs have morphed into slick, cinematic affairs, but he advises children against feeling the need to always be "camera-ready".

"Just be genuine," he says.

"If you're faking the best version of yourself, it will show over time.

"If you're sharing your genuine high points, along with maybe your not-so-high points, people will respect and like you for being real."