What do Baby Shark, the Harlem Shake and Gangnam Style have in common?

Overplayed? Annoying? You’re entitled to your opinion.

But what’s not in doubt is that they all went viral on YouTube, which is now 20 years old.

It’s become the place where 2.5 billion people log on monthly to kill time, be entertained and, sometimes at least, learn something.

But it’s also been life-changing for some of its breakout stars, like Charlie.

You wouldn’t recognise him now but millions around the world have watched him, as a baby, chomping on his big brother’s digits.

That’s because he’s the star of Charlie Bit My Finger.

“It was never not a part of my life, it’s always been there,” Charlie, who’s now 18, tells BBC Newsbeat.

The 55-second clip has had almost 900 million views since it was uploaded in 2007.

Charlie, now 18, says he can’t remember the moment, filmed when he was “about one” and sitting on Harry’s lap.

He says the clip’s success has made life “easier” and helped him get to university where he now studies law.

His dad Howard Davies-Carr previously told Newsbeat the family had made an estimated £1,000,000 off the video over the years.

The video was sold as a non-fungible token, or NFT, for £500,000 in 2021.

But Mr Davies-Carr said he wanted to keep the boys “very grounded” in how they live their lives.

Charlie shares that view and says he doesn’t play the “don’t you know who I am?” card.

“It’s not like I use it as an icebreaker or anything,” he says.

“I was never going to use this as a fun fact.”

Charlie says he doesn’t want to be seen as a show-off, so when asked about himself volunteers “something else a bit more boring”.

“But my friends like to tell people [sometimes], so it’s hard keeping it locked down,” says.

“It slips out every now and then.

“And people are like: ‘Oh that’s cool’, for like five minutes. Or they say: ‘I don’t know what that is.'”

YouTube was founded on 14 February 2005 by three friends – Steve Chen, Chad Hurley and Jawed Karim – all former employees of the online payment system PayPal.

While the first video published on 23 April 2005 was not quite Baby Shark, it did have an animal theme.

It was a 19-second clip called Me at the zoo, posted by co-founder Jawed.

The founders opened the first YouTube headquarters in an office above a California pizza restaurant.

It is now owned by Google and has offices all over the world.

In the UK, 82% of adult internet users in the UK have reported using the platform – more than WhatsApp (80%), Facebook (76%) and Instagram (57%).

Now YouTube is a destination many choose for the latest trailers, reviews and news.

But it is music videos which dominate the most-viewed list, with Baby Shark Dance having more than 15 billion watches.

Despacito by Luis Fonsi has more than eight billion, Shape of You by Ed Sheeran has more than six billion views and PSY’s Gangnam Style has 5.4 billion.

And while Charlie’s family has been helped by income from YouTube, some of its biggest names have made a fortune.

American YouTuber MrBeast, a.k.a Jimmy Donaldson, is the most popular YouTuber with more than 360 million subscribers.

Business magazine Forbes estimates that he earned $85 million (£68 million) in 2024, making him the highest-paid creator.

But it hasn’t all been smooth sailing in the platform’s two decades.

Fact-checking organisations around the world have previously said that YouTube is not doing enough to prevent misinformation on the platform.

The site has also been punished for privacy violations, being fined $170m (£139m) by a US regulator for violating children’s privacy laws.

In 2023, it was accused of collecting the viewing data of children aged under 13, in breach of a UK data privacy code.

And there has been criticism that, like other online platforms, violent and extremist videos have been available to view despite government calls for their removal.

Journalist Tamzin Kraftman, who covers technology news, feels while the platform has managed to stay relevant against competition from TikTok and Instagram, there are challenges with combating things like misinformation.

“No team can go through everything with a fine-toothed comb,” she says.

“So the question is how they will ensure everything on there is correct and within regulations.”

Tamzin tells Newsbeat AI could play a big role in helping to deal with those issues, but “might get things wrong and could ban the wrong channel”.

“I think it’s how they use new tools to really stop the spread of misinformation that is going to be their golden ticket [going forward].”

And Charlie doesn’t think the platform is “dying out” any time soon, years on from his flutter with fame.

While he doesn’t remember loads from then, he is grateful for the opportunities it has brought.

He has managed to travel “a decent amount” and been to the United States, filming a flight-safety video.

As for whether he’s tried to recreate the bite?

“I haven’t since I was very young.

“I could start charging now. But I feel like I’ve lost my ability,” he says.

Listen to Newsbeat live at 12:45 and 17:45 weekdays – or listen back here.