12 algorithm myths, checked against what the platforms actually published

“Every video is tested on a small random group first.”

There is a first audience, and on Instagram it’s official. Instagram says that, for recommendations, every eligible post is first shown to a small audience it thinks will enjoy it, whether or not they follow you; as that audience engages, the top-performing reels go to a slightly wider audience, then a wider one again. confirmed · 1 The wrong word is random. Even Instagram’s description is a prediction: an audience it thinks will enjoy the post. confirmed · 1 TikTok, YouTube and X don’t describe a test group, but they describe the same kind of prediction. TikTok ranks each viewer’s feed by how likely that viewer is to watch, finish, share or skip each video. confirmed · 2 In YouTube’s 2016 paper, each viewer is shown only the highest-scoring candidates. confirmed · 6 X’s current code lifts a small account’s new post only in feeds where it was already picked as a candidate and scores highest among eligible new posts. confirmed · 17 TikTok also shows people different videos from time to time, partly to learn what’s popular with wider audiences. confirmed · 3 So the first people to see your video are mostly the ones it’s predicted to suit, and the test is whether they actually watch it. inferred How big that first audience is, how long the test runs and what counts as a pass: no platform publishes any of it. “100 people” is a guess.

so Make the video for a specific audience, so the right people get picked. Then make them watch more and more of it. inferred On Instagram you can also run a version of the test yourself: trial reels go to non-followers first. confirmed · 14

“The first hour decides everything.”

No published paper or official page gives a window in which an ordinary post’s fate is decided. What is confirmed is that early reactions travel fast. Meta says its very large models can be updated within minutes, and that they refine their picture of each person after reactions such as watching a whole video. confirmed · 18 Instagram counts how quickly people engage with a post as a popularity signal, one it says counts much more in Explore than in Feed or Stories. confirmed · 12 X is the one platform with a published clock for its main feed: For You drops posts older than 48 hours, and its new-author lift only applies to posts under 48 hours old with fewer than 1,000 views on the Home timeline. confirmed · 17 A golden hour, as a rule, is folklore with a stopwatch.

so Post when your people are around, and judge a post by who reacted and how, not by its first-hour total. inferred

“There’s one algorithm.”

Instagram says Feed, Stories, Explore, Reels and Search each rank posts their own way, and Meta’s engineers describe more than 1,000 models behind its recommendations. confirmed · 12, 16 YouTube says it built separate recommendation systems for Shorts and long videos. confirmed · 11 X’s published code chains separate services to find posts, score them and filter them. confirmed · 17 “The algorithm” is shorthand for a stack of systems, each tuned for its own part of the app. inferred

so Give each post one job. On Instagram, Stories only reach people who follow you, while the Reels tab is mostly accounts the viewer doesn’t follow. confirmed · 12

“Likes are what the algorithm wants.”

Likes count, but as one predicted action among many. confirmed · 2, 12, 17 TikTok says that for many users, time spent watching is generally weighted more heavily than other factors. confirmed · 4 Instagram’s creator FAQ says what matters most for distribution is engagement per viewer: watch time, sharing, following, liking, commenting and profile visits. confirmed · 13 X is the only one that prints its numbers: a predicted like is worth 0.5, a reply 5 and a share by copied link 20. confirmed · 17

so Build for the action each platform names: watching on TikTok and YouTube, full watches and reshares on Reels, replies and shares on X. inferred

“Longer videos win, because platforms count watch time.”

YouTube’s 2016 ranking was built on expected watch time per impression. confirmed · 6 On its own, that leans toward videos that keep people watching longer. inferred Today YouTube says there is no universal ideal length, names average percentage viewed next to view duration, and advises against filler. confirmed · 8, 9 In 2020 TikTok called finishing a longer video a strong sign of interest. confirmed · 3 Instagram doesn’t recommend reels over 3 minutes to people who don’t follow you. confirmed · 13 Length pays only when people stay. inferred

so Make it as long as the idea needs, then cut what people would skip. inferred

“One bad reaction costs more than a like earns.”

On X, chance for chance, yes. It’s the one platform that prints its weights. confirmed · 17 A predicted “not interested” counts −43.2, a mute −58.8, a block −31.2 and a report −234, against +0.5 for a like. confirmed · 17 X’s own code adds two cautions: the weights multiply one viewer’s predicted chances, not counts, so “one report cancels 468 likes” is the wrong reading, and a report is weighted heavily partly because it’s over 1,000 times rarer than a like. confirmed · 17 TikTok, Instagram and YouTube all use “not interested” as a signal but publish no sizes. confirmed · 2, 9, 12 Elsewhere, the exact trade is unknown.

so A hook that wins the tap and loses the viewer is a bad trade everywhere. inferred

“Shadowbans are real.”

Reduced reach without removal is real, and every platform here documents a version of it. A post can be allowed on Instagram but kept out of recommendations, and after repeated violations all of an account’s posts can be left out for a period. confirmed · 12 In their 2023 version, TikTok’s For You standards keep some allowed videos off For You while they stay findable by search or by following. confirmed · 5 YouTube demotes borderline videos. confirmed · 10 On X, labels such as “do not amplify” can stop a post reaching non-followers while followers still see it. confirmed · 17 The secrecy is only partly gone: Instagram’s Account Status shows whether your content can be recommended, and X is piloting a tool called Under the Hood that shows the labels on your account and posts. confirmed · 12, 17 Instagram also says it doesn’t hide posts to sell ads; that one rests on its word alone. confirmed · 12

so Before you blame a ban, check Account Status or Under the Hood, and the platform’s eligibility rules. inferred

“Hashtags get you reach.”

The right ones can help. Instagram says trending hashtags that match your reel’s topics can help it reach people interested in those topics, and warns that irrelevant ones can hurt engagement and then distribution. confirmed · 13 TikTok lists hashtags among the details it uses about a video, in 2020 and today. confirmed · 2, 3 No published paper or official page says piling on popular hashtags adds reach.

so Use a few that describe the video to the people you want. They help the system pick the right first audience. inferred

“Instagram pushes down reels with a TikTok watermark.”

Instagram says so itself. It aims to make reels less visible when they carry a watermark, and also when they’re low-resolution, muted, bordered, mostly text or already posted on Instagram. confirmed · 12 The wording covers any visible watermark, not TikTok’s alone, and its 2024 rules for recommendations ask for no visible watermarks. confirmed · 1, 12 Copies get the same treatment. TikTok’s 2023 eligibility standards list reposts without new or creative edits as ineligible for For You. confirmed · 5 Instagram leaves accounts that repeatedly repost others’ content without material changes out of recommendations: 10 or more times in 30 days, under its 2024 rule. confirmed · 1 Since April 2026 that also covers photos and carousels. confirmed · 15

so Export a clean file for each app, and post originals. If you build on someone else’s video, change it for real. inferred

“Big accounts get pushed, and small ones can’t break through.”

Size helps, mostly through your followers. inferred Instagram even named follower count itself as a Reels signal in 2023. confirmed · 12 In 2020 TikTok said follower count and past hits are not direct factors in For You, while admitting bigger accounts are likely to get more views. confirmed · 3 Instagram said in 2024 that recommended reels had been ranked mainly on how an account’s followers engaged, so the largest accounts often got the most reach, and that it was adding a ranking input to give smaller creators more distribution. confirmed · 1 X’s code can lift one new original post per refresh from an account with 1,000 or fewer followers, if the post has had fewer than 1,000 Home views. confirmed · 17 So the myth was closer to true on Instagram before its 2024 change. inferred

so If a video flops on a small account, it’s more likely about that video than about your size. inferred

“Posting more often gets rewarded.”

No source I read rewards volume. YouTube’s help page for Shorts says there’s no minimum posting cadence for videos to do well. confirmed · 7 X discounts each extra post from the same author in one refresh, never below a quarter of its score. confirmed · 17 TikTok said in 2020 that For You generally won’t show two videos in a row from the same creator. confirmed · 3 And YouTube says one video’s underperformance doesn’t penalize a channel overall, though a channel can suffer over time if particular viewers consistently stop watching its videos when they’re recommended. confirmed · 8

so Post when you have a video your audience will choose. A few they pick likely beat many they skip. inferred

“My reach dropped, so the algorithm changed.”

Maybe. Weights do move: TikTok says the weighting of its factors can change over time confirmed · 4, and X’s repository documents a reply boost it began testing on 10 July 2026, rolled out widely on 13 July and scaled back on 24 July. confirmed · 17 But YouTube names outside reasons too: how many people care about your topic, competition, and seasons such as major holidays. confirmed · 8, 9 From outside, you can’t tell which one hit you. inferred I watch videos all day, and I still can’t see what TikTok or Instagram changed last week. Nobody outside can.

so Compare several posts before you change course, and check the outside reasons first. inferred