It's 2021, if you've not crossed paths with a few TikTok videos (if you don't have the app downloaded) on WhatsApp, Instagram, or Facebook, you're living under a rock. It's the most popular short-video app which has all kinds of audiences, right from gen Z to boomers. But here's the thing, a Gen Z person's feed will have different content than a boomer's feed. Not just that, there's a possibility that every Gen Z person who opens the app will see different videos on their feed. TikTok calls this the "for you" feed because of the extreme personalization of the content. Okay, but how does their "for you" recommendation system work? Recently, the company disclosed the secret mantra behind the success of the app and what makes sure the system does not create any filter bubbles which is a feed where one sees a homogeneous stream of videos.

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The secret is out! The app takes into account the videos a person likes or shares, the accounts they follow, the comments they post, and the content you create to find out what your likes are. Apart from that, the recommendation system will also capture video information like captions, sounds, and hashtags associated with the content the person likes.

The company wants to keep it hush-hush but it will also use the person's device and account settings information like the language preference, company setting, and device type. But according to TikTok, these factors are at the lower end of the recommendation system compared to other factors because they want the system to be optimized for performance.

Do you often watch TikTok videos from start to end? The algorithm might count that as an interest. This factor will be given more importance to the algorithm than the location of the user's device.

Ever wondered how a video gets a million views while others get mere hundreds? TikTok says if the video is posted from an account that has more followers, the video will get more reach. But this isn't a direct factor. TikTok top user accounts like Zach King, Addison Rae aren't guaranteed a direct path to the "For You" page of every user, even if the user follows them. The algorithm takes into account the users changing interests and preferences, notes all the new accounts that are being followed and unfollowed, tracks hashtags, sounds, effects, and trending topics on its discover tab. All these tailors a personalized TikTok experience. Users can also signal the app what their likes and dislikes are with a long press by which they can either add a video to their favorites or mark "not interested".

Like any other app that runs on user input, a user's initial encounters with the app are bland because the algorithm doesn't know what the user likes. To address this, it asks new users to select categories of interest, like pets or nature, to put the puzzle in place. TikTok also says it also understands that catering too much to someone's individual state can lead to a limited experience called the filter bubble.

To create diversity in the kind of recommended content, TikTok will add videos to the user's "For You" feed that is not of the person's interest in an attempt to expand their viewer base and give new content creators a chance. This is a problem faced by Facebook, Instagram, and Youtube that has not well addressed. Their algorithms often keep the user in their bubble. TikTok believes this is the disadvantage of personalization.

"By offering different videos from time to time, the system is also able to get a better sense of what's popular among a wider range of audiences to help provide other TikTok users a great experience, too. Our goal is to find a balance between suggesting content that's relevant to you while also helping you find content and creators that encourage you to explore experiences you might not otherwise see", said TikTok in a blog post.

This disclosure on how the algorithm works was announced at the time when there were major antitrust investigations happening in the U.S and EU and TikTok was under congressional review for its ties with China. Since then, TikTok has been working to change its perception in the U.S by forming a Content Advisory Council and opening an LA facility, the TikTok transparency center, where external experts can view the company's source code and its moderation practices in action first-hand.