I vividly recall the first time I saw Grotbags, the witch played by Carol Lee Scott, who died last week. I was at a friend's house after school – partaking in what the kids these days might call a “play date” – when a leering green face appeared on the TV screen. Grotbags was three decades ahead of the curve in terms of eyebrow enhancement, and with her tight synthetic ringlets she was too close for my comfort to the most terrifying creature of all – a clown. I asked my friend what horror I was watching, and she explained this was channel three.

I had never heard of channel three. In my house we had BBC One and BBC Two, as per the listings in the trusty Radio Times. If you wanted to watch Children's BBC, you walked over to the TV and pressed the power button, followed by one. I appreciate my ignorance of other options suggests a remarkable lack of curiosity, but channel-surfing was an alien concept for our family. It was something we attempted – and comprehensively failed at – on summer holidays to coastal Devon. As a result, my idea of children's TV was a cheery man in a broom cupboard with a puppet duck, not a witch in a windmill giving everyone the heebie-jeebies.

The extra channels weren't a secret, but my parents reasoned they weren't essential viewing. After all, the sooner we started watching STV, the sooner we'd start hankering after a Fashion Wheel, or a Play-Doh Fun Factory, or a community of Sylvanian Families. We'd be lured by advertisers into deploying “pester power” to get whatever pieces of plastic they were pushing between programmes.

These days there is no escape, and the idea of restricting children's viewing of toy adverts seems laughably naïve. We can barely manage to stop them seeing beheadings and hardcore pornography, let alone commercials for alcohol, tobacco and junk food. In the face of those threats, it's perhaps little wonder the modern approach to toy-promotion has escaped scrutiny. These days, manufacturers need not create glossy adverts and pay for them to be broadcast in between Wacky Races and Looney Tunes. Instead, they can simply send their products to young “influencers” with a flair for the dramatic. With a marketing director – sorry, parent – sitting behind the camera, these youngsters create “unboxing” videos. In other words, they are filmed opening the toys, playing with them and talking about them.

You've probably never heard of “Bad Baby Tiana” or the “Toys And Me” YouTube channel – unless, that is, you spend a lot of time with a child who spends a lot of time online. In February this year, hundreds of people queued up outside a toy shop to meet this English nine-year-old, who “unboxed” herself by punching her way out of a giant drum before launch a new range of dolls and taking part in a “meet and greet” with her fans. Toys And Me has five million subscribers, and Tiana's most popular video – involving giant lollipops – has been viewed a staggering 239 million times. These views translate into cash thanks to YouTube adverts.

Setting aside the very important question of whether Tiana is being exploited here – and what will happen when she hits puberty and doesn't want to play-act the role of a bad baby any longer – it's worth asking why her videos are so popular to begin with, and to what lengths parents will go to get those lucrative clicks.

Children, it turns out, really enjoy watching other children online. And, with apologies to anyone still eating their breakfast, they also enjoy watching videos involving “poop”. It follows that making a video combining a young YouTube sensation with something resembling faeces is therefore a sure-fire way to become filthy rich – or at least it has been until recently. Thanks in part to a newspaper investigation into the murky (and indeed stinky) word of YouTube advertising, big-name brands have realised there's a downside to hawking their wares based on algorithms rather than human judgement. I do not suggest you follow me down the rabbit hole by looking up any of these utterly bizarre videos, but it's worth knowing your children or grandchildren might be among the millions seeking them out (one of the auto-fill search options is a very polite “poop videos please”).

When I watched them the only adverts that popped up were for air fresheners and Dettol – possibly because YouTube knows I'm a 35-year-old woman and not a tween – but even if advertisers aren't directly supporting scatological scenes, they're feeding the trend indirectly by working with those who make them.

Suddenly Grotbags, despite her name and her creepy complexion, doesn't seem quite so horrifying after all. I'm away to buy some Dettol.