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TikTok reveals details of how its algorithm works

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Re: TikTok reveals details of how its algorithm works

#51
post #8

It's a (seemingly) pretty simple matter of keeping track of how long someone looks at a video, and optimizing to show them videos they'll spend a long time looking at. It's pretty powerful too, I spend much more time looking at TikTok than any other digital content aggregator (to the extent I had to delete it from my phone). They also do some things like sprinkle in random fresh videos, potentially unrelated to your…

I actually think it's got much more to do with the training data. Given that you are watching a video, you need to either swipe away from it, or finish watching it. This provides either a 1 or 0 for the video classification model. The important contrast here is with FB/IG feed where you can scroll aimlessly without engaging, leaving you with perhaps 1 engagement out of 10 (or whatever). The attached doc suggests that…

What surprises you about the unsupervised learning?

Re: TikTok reveals details of how its algorithm works

#52

Earlier quoted context omitted.

feel like dating apps do something similar... but I wonder why I end up in YouTube holes with bottomless pits though until I hit the reset button.

Probably YT algorithm fall into a local maximum where it detected that X is enraging enough, then creators notice that the X is popular and they start putting more X, then the algorithm is putting more weight behind X and you are now stuck here.

Not because of that, but because YouTube does not have human curators.

Re: TikTok reveals details of how its algorithm works

#53

don't see how tiktok is so game changing? How long can one look at random dance videos? What demographic would maintain sustained interest over years? flavor of the month/year?

How many minutes have you spent watching TikTok?

i had an account for a few weeks.. followed a few folks.

However my assessment is a video has much less revisit value than still images. The nature of a video requires much more time investment. Audience has to remain focused on a video for a period of time to achieve full reward. Unlike a still image, where a quick glance can gain satisfaction.

These platforms can not sustain on pure novel content. The model of user engagement must include revisit of content. You see a thumbnail of a video you've liked or have seen before. What is the threshold of intrigue, that will propel you to invest x amnt of time fully dedicated to that video content?

If my opinion above holds true, tiktok will not be a lasting phenomenon. The content will not keep up.

Re: TikTok reveals details of how its algorithm works

#54
post #9

Earlier quoted context omitted.

More data beats smarter algorithms any day, and TikTok gets a lot of data because its videos are so short and interaction rate so high. There are tons of signals it can use as inputs: How much of a video did you let play before swiping next? How many times did you let the video loop? Did you like? Did you comment? Did you like a comment? Did you click through to the profile? Did you view other videos from the profile…

> Did you click through to the profile? Did you view other videos from the profile? Probably why multi-part videos are so popular (you have to click their profile then find the part 2 video to finish the story they were telling).

Sounds like a way to game the system.

Re: TikTok reveals details of how its algorithm works

#55
post #9

I don't see any details about its algorithm, just that they use a recommendation engine? Things like this aren't proprietary info, they're just how recommendation engines work: "Once TikTok collects enough data about the user, the app is able to map a user's preferences in relation to similar users and group them into "clusters." Simultaneously, it also groups videos into "clusters" based on similar themes, like "bas…

More data beats smarter algorithms any day, and TikTok gets a lot of data because its videos are so short and interaction rate so high. There are tons of signals it can use as inputs: How much of a video did you let play before swiping next? How many times did you let the video loop? Did you like? Did you comment? Did you like a comment? Did you click through to the profile? Did you view other videos from the profile…

I don't buy this argument. YouTube ostensibly has a metric ton of information like this and even if tiktok has more training data now, I'm fairly sure their training data in principle was smaller than what YouTube historically had given their decades long presence and their ubiquity in the internet.

This is on top of the documented effort by YouTube to perfect their recommendation algorithm using the best ML minds they got [1] only to polarizing response from its users.

Clearly tiktok has other advantages (homogeneity in some content characteristics, viz. Extremely short videos which probably correlates to their simplicity) and has clearly tuned a fundamentally better recommendation algorithm that even the minds at Google brain couldn't figure out.

[1] https://www.theverge.com/2017/8/30/16222850/youtube-google-b...

Re: TikTok reveals details of how its algorithm works

#56

Not much of a reveal. What I find strange about TikTok are the waves of themes I get to see. Being a 50-something I'm probably not the target audience but at first all I saw was shuffle dance (enjoyed that) followed by Indian and Chinese manufacturing videos (loved those) and now it's all cats (okay with that). My daughters explained "Elite TikTok" and "Beans TikTok" so now I realize there's a whole world built on to…

The recommendation algorithm generally tries to avoid showing directly similar content. It's surprising it is all cats especially if you ever swipe. Perhaps this is an A-B test and you are in a group with lower boredom avoidance settings :)

Can you explain a bit more about Elite TikTok? I found this article but it contains quite a jumble of ideas https://www.theguardian.com/culture/2020/jun/22/what-is-elit...

Re: TikTok reveals details of how its algorithm works

#57
post #18
post #15

Earlier quoted context omitted.

I’d say it’s more likely they have super advanced/clever ways of doing the latter. The algorithm could be a simple dot product and the result could be great or terrible depending on how good the feature extraction is. Pulling useful features out of videos is no small task. The fact that everyone raves about how good the recommendations are indicates to me that this is where their innovation lies.

There's so much good meta-data (likes, comments, duration, sound used, views, like/view ratio, skips, loops, subscribes, etc.) that I'd be surprised if they were digging into the contents of the video at all right now.

They claim to be looking at the music in the video and avoiding sending you to another video with the same music.

Re: TikTok reveals details of how its algorithm works

#58
I didn't see anything in there about how their algorithm prevents people from seeing videos involving poor people[1] or Hong Kong protests[2]. Maybe that's part of the secret sauce.

[1] https://theintercept.com/2020/03/16/tiktok-app-moderators-us...

[2] https://www.washingtonpost.com/technology/2019/09/15/tiktoks...

Re: TikTok reveals details of how its algorithm works

#59
post #8

It's a (seemingly) pretty simple matter of keeping track of how long someone looks at a video, and optimizing to show them videos they'll spend a long time looking at. It's pretty powerful too, I spend much more time looking at TikTok than any other digital content aggregator (to the extent I had to delete it from my phone). They also do some things like sprinkle in random fresh videos, potentially unrelated to your…

I actually think it's got much more to do with the training data. Given that you are watching a video, you need to either swipe away from it, or finish watching it. This provides either a 1 or 0 for the video classification model. The important contrast here is with FB/IG feed where you can scroll aimlessly without engaging, leaving you with perhaps 1 engagement out of 10 (or whatever). The attached doc suggests that…

Reducing engagement data to 0/1 would lose a lot of precious data, it treats getting 50s through a 1m video worse than watching the whole of a 5s clip, and watching a 2s clip the same as watching a 2s clip on loop 20 times because it's so incredible. Given the point of the app is to get people on it for a long time, it would make much more sense to track number of seconds watched and train to maximize that.

Re: TikTok reveals details of how its algorithm works

#60

To be fair, the algorithm they told is mostly what we would have perceived, knowing if that is Machine Learning driven. Although, I am quite intrigued what they would be showcasing in their "transparency centers". If they show what extent their data can be utilized. and not simply a simulation of the ML stuff.

> To be fair, the algorithm they told is mostly what we would have perceived, knowing if that is Machine Learning driven.

Indeed.

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