Viral videos flit around on You Tube like so much digital litter.

Endless variations on Hitler's downfall; Lady Gaga being hit by a piece of stage scaffolding; the odd dancing gerbil. We've all seen them. But occasionally, amidst this maelstrom of the mad and the mundane, one settles on your desk that is of another order entirely, that is like a precious butterfly that you want to cup in your hands and cherish before releasing to your friends.

One such is the talk "If I should have a daughter", given by the young US performance poet Sarah Kay at the annual TED (Technology, Entertainment, Design) conference in California last year. Parents and would-be parents and non-parents and high school children with low grades and high school children with no grades and hoodies and the bullied and the fat and the thin and kids who don't "get" poetry at all – they've all been moved by this, wished that Kay was their teacher, mother, sister, friend.

Be warned – this deceptively simple talk can unhinge you, leave your emotional door hanging wide open.

It is beautiful and powerful, driven by Kay's engaging youthful sincerity, her complete lack of cynicism, her telling images.

Addressing the daughter she doesn't yet have, she says: "She's gonna learn that this life will hit you hard, in the face, wait for you to get back up so it can kick you in the stomach. But getting the wind knocked out of you is the only way to remind your lungs how much they like the taste of air."

In spite of the difficulties any life faces we need to say thank you "because there is nothing more beautiful than the way the ocean refuses to stop kissing the shoreline no matter how many times it's sent away".

Born in 1989, Kay is something of a star in the US, having first performed at the Bowery Poetry Club in Manhattan at the age of 14.

She hates what you might call the curse of cool and believes in going through life with outstretched arms – we don't avoid hurt that way, "but it also means that when beautiful, amazing things just fall out of the sky, I'm ready to catch them".

Her talk is easy to find – entering "Sarah Kay daughter" does it – and is very affecting. My own daughter watched it – and then sent this butterfly on to a friend.