But instead of being comforted, the youngsters are attacked by notoriously cruel online commentators.
The worrying trend has mushroomed of late, though the videos first started appearing two to three years ago.
One video, uploaded by sgal901, sees a pretty young blonde asking whether she is ugly and posing in a selection of photographs.
Her film has been watched more than 3,505,000 times since being uploaded in December 2010.
A lot of people tell me I'm ugly. I think I'm ugly and fat, she says to the camera.
The comments that follow are either over-the-top compliments, suggesting sex, or painfully cruel.
One watcher wrote: "This is such a stupid video......What stupid person would record a video like this one and then upload on YouTube don"t they notice that they are just embarrassing their self by the way you are ugly the only thing I see in this video is ugliness I see no beauty."
Others are kinder.
One wrote: "Ignore those who comment 'ugly'. My opinion; You're super pretty."
There are scores of others similar videos, their subjects wide-eyed and naive.
Beautifulandproud posted a clip on December 2, 2011. She seems distraught and the video is heartbreakingly sad. She asks the question simply and gives no background or details.
"A lot of people tell me I'm ugly. I think I'm ugly and fat." She says.
Faye, going by the YouTube name of Smilelovebeauty8, explains that at school she is often told she is ugly, but her friends tell she her she is pretty, so she asks YouTube viewers to tell her what they think.
The replies are abusive and crude.
But while the majority of videos are made by girls, they are not alone. Boys are asking the same question and comments are just as vicious and snide.
Parentdish editor Tamsin Kelly said: "It's so sad to see young people so insecure about their looks and so naïvely displaying their anxieties to total strangers. It's an alarming step up from teen girls posting Facebook pics of themselves posing in new outfits or make-up and looking for compliments from their friends.
"As parents we strive to bring our children up to be happy and confident in their skins and if they are unhappy with their looks to come to their family and friends for reassurance. That's what makes these videos so heart-breaking - that these sad teens are turning to the internet and anonymous eyes rather than real support."
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