Momo has indeed become a YouTube fixture, as a subject of analysis, as a joke, and as a troll. On Friday, YouTube it was "demonetizing" (withholding ads from) all videos that contain Momo, suggesting that surge of attention had made posting videos about her particularly profitable.
And it's not just YouTube. There is a Momo who is supposed to haunt Snapchat. There's another who crashes videos of Fortnite, a uniquely popular game among young children. Momo meets kids where they are — or at least where their parents think they are.
For years, in various online spaces, young people have been writing horror stories, often pseudonymously or in an iterative group process. Their tales are known colloquially as "," an iteration of the term "copypasta," shorthand for passages or blocks of text or chain-letter-type stories that are frequently copied and pasted in a given online community. The authors of these posts do so to scare each other, with the occasional bonus of going viral. (The Slender Man character, which inspired multiple games and a feature film, gained popularity through copypasta. Momo's virality no doubt owes to the of a young girl by two of her friends, who later said they were influenced by the Slender Man.)
Momo is what happens when the grown-ups start writing copypasta of their own, about their own biggest fears: what their kids are doing on the internet, and what the internet is doing to their kids.
The spaces where Momo is believed to flourish share in their tendency to make parents anxious anyway. It's 10 p.m. — or let's say 7 a.m., or 5 p.m. — and parents do know where their children are: transfixed by their phones or tablets, rapt by a chain of endlessly recommended YouTube videos made by strangers motivated by advertising dollars.
The older kids are chatting with their friends, or people they say are their friends, and spending countless hours talking to each other in language that, to their parents, may as well be code, in a game that feels like a social universe unto itself. Children spending time with screens is commonly contrasted with children spending time outside, or doing some other supposedly more enriching activity, but the shape of the Momo panic is informed by age-old ideas about "stranger danger."