What made TikTok such a success? A commonly given reason is that the app’s advanced AI is really good at figuring out what you want to watch. Many people say TikTok knows them better than they know themselves. Some users think of the algorithm as a divine force that guides them.I’m not here to question people’s lived experience of TikTok. But there’s no truth to the idea that TikTok’s algorithm is more advanced than its peers. From everything we know—TikTok’s own description, leaked documents, studies, and reverse engineering efforts—it’s a standard recommender system of the kind that every major social media platform uses. Besides, recommender systems are a topic of furious research in computer science, and it would be implausible for TikTok engineers to have made a breakthrough that no one else knows about. Companies stay at the cutting edge by having their researchers and engineers participate in the open culture of knowledge sharing at conferences such as RecSys. A company walling itself off will only get left behind. For all these reasons, I don’t believe TikTok’s algorithm is its secret sauce.Why, then, does TikTok’s algorithm feel so different? The answer has nothing to do with the algorithm itself: It’s all about the design.