For most of the last decade and a half, Google has been the most visited web domain in the world, and it's not even close. The last time another site posed a real challenge for the top spot was Yahoo, and that was a decade ago.

When you consider the number of people who use Google's services every day for everything from school assignments, collaborating on documents, finding directions, sharing photos, and well, searching for just about everything, it's not all that surprising. Google is the most popular search engine in the world, and it's where the vast majority of people start when they want to find something online.

Somewhere close to half of all internet traffic originates with a Google search. That dominance has made Google the world's largest advertising platform--not to mention the most profitable. 

This year, that has been changing. According to a report released on Monday by Cloudflare, one of the major internet content delivery networks, TikTok.com overtook Google as the most visited domain in the world in 2021. 

On the one hand, considering how relatively new TikTok is in our collective consciousness, that's surprising. On the other hand, when you remember TikTok is the fastest-growing social network ever, it shouldn't be. It was even the most-downloaded app in 2020 and now has more than 1 billion users. 

TikTok's rise to the top clearly says something about how technology is changing, but more importantly, it says something about the change in the way we find and consume information about the world around us. For more than a decade, the way we use the internet has mainly been dominated by Google, Facebook, YouTube (which is owned by Google), and Amazon. If you happened to find yourself somewhere else online, there's a good chance you started at one of those sites. 

However, that's becoming less the case, especially with younger users. TikTok is more popular among teenagers than Instagram or Snapchat. Despite that, TikTok isn't just videos of memes or teenagers dancing. Some of the most popular content are beauty tips, recipes, and how-to videos. That's squarely in the lane occupied by Google, YouTube, Facebook, and Instagram. 

It also means that people aren't just using TikTok for entertainment, but for information. That's a massive shift, and it has real implications for every other platform.

TikTok is quickly becoming a real threat to the established tech giants in a way almost no one expected. It makes sense that a new social media platform could take away attention from Facebook, or Twitter, or Instagram, but Google? The place we go for information about, well, everything? That's a shift that most people wouldn't have predicted because it doesn't fit our understanding of how people use technology. 

Let's set aside privacy or security concerns about TikTok, which is owned by a Chinese company, Bytedance. We'll also ignore the absurdity of the previous administration trying to force a sale first to Microsoft, then to Oracle. That only distracts from the reality that TikTok has become a far more integral way to access information that most people understood or expected.

Of course, it isn't without problems. Any platform that relies on user-generated content faces the same challenge of what to do with that content when it crosses a line. TikTok has its share of misinformation, as well as racist and incendiary content. And it isn't clear it has had any better luck moderating its platform--but, as it continues to grow, that becomes more of a concern.

TikTok is still small compared to its competition in almost every other measurement. Its Chinese parent company is private, so it's impossible to know exactly how much revenue it brings in. Still, analysts think TikTok had around $2 billion in revenue in 2020, a number that is a rounding error compared to Google ($181 billion) or even Facebook ($86 billion). That, however, means it has enormous room to grow. 

There's a certain amount of irony that while the established tech giants have attracted intense scrutiny from lawmakers and regulators on both sides of the Atlantic, they're already in the process of being disrupted by an app that most of them didn't take seriously. The real lesson here is that established businesses and institutions are notoriously slow at recognizing the thing that will replace them. 

They assume that their main competition is what they can see in front of them. Sometimes, however, it's something no one took seriously until suddenly it's not just a shiny new thing that everyone assumes will fade with time, but a real threat. By then, it's probably too late.