"The algorithm" gets discussed as an adversary with moods. It is more usefully understood as a prediction system with one job: estimate how likely a given person is to engage with a given piece of content, and rank accordingly. Almost everything else follows from that.
The basic sequence
- Classification. The platform works out what your content is about, using the caption, hashtags, transcribed audio, on-screen text, visual content, and the history of your account.
- A small test audience. Your post is shown to a limited group — some followers, some non-followers with matching interests. This is the phase that decides most outcomes.
- Measurement. The system observes what that group does: watch time, rewatches, saves, shares, comments, and how quickly they scroll away.
- Expansion or stop. Strong response means a larger audience and another round. Weak response means distribution effectively ends.
- Repeat. Each successful round widens the audience, which is why viral growth looks stepped rather than smooth.
This structure explains several things that otherwise seem strange — including why a post can sit flat for hours and then take off, and why two similar posts can perform completely differently. The test-audience draw is not identical each time.
The signals, roughly ranked
| Signal | Weight | Why |
|---|---|---|
| Watch time / completion | Highest on video | Hardest to fake, closest proxy for genuine interest |
| Rewatches | Very high | Almost unambiguous — nobody rewatches by accident |
| Shares and sends | Very high | Costs the sharer something; strong quality signal |
| Saves | High | Indicates lasting value rather than passing interest |
| Comments | High | Effortful, and generates dwell time |
| Scroll-away speed | High, negative | A fast skip is a strong negative judgement |
| Likes | Low | Cheap, ambiguous, easily habitual |
| Follows from post | High | Indicates you reached the right audience |
The pattern is that signals are weighted roughly by how much effort they cost. That is a sensible design: effortful actions are harder to game and better correlated with genuine interest.
Why the first minutes matter
Because distribution expands in rounds, early performance compounds. A post that does well in its first test round gets a larger second round, and so on. A post that does poorly early does not get a second chance, regardless of how good it would have looked to a wider audience.
This is the mechanism behind advice about posting when your audience is active, and it is one of the few pieces of timing advice with a real basis. It is also why the opening seconds of a video matter disproportionately — they determine the early watch time that decides whether there is a second round.
Where hashtags sit in this
Hashtags contribute to step one — classification. They help the system decide what your content is about, which affects which non-followers are in your test audience. That is genuinely useful, and it is also a much smaller role than hashtag advice implies. They influence who gets tested, not whether the test succeeds.
Which explains a common frustration: better hashtags produce a modest improvement, not a transformation. They are aiming the shot, not powering it.
Things commonly attributed to the algorithm that are not
- "Reach is down because of a penalty." Usually it is variance, or content that performed less well. Genuine penalties are rare and mostly tied to policy violations.
- "The algorithm hates links." Not a rule so much as an effect — posts sending people off-platform tend to produce less on-platform engagement, which the system reads accordingly.
- "Posting at the wrong time killed it." Timing affects the early test round, so it has real but modest impact. It does not override content quality.
- "Editing a post after publishing hurts it." No good evidence for this.
- "Following too many accounts hurts your reach." No.
What actually follows from all this
- Make the opening strong. It determines the test round, and the test round determines everything downstream.
- Optimise for effortful actions. Content worth saving or sending beats content worth liking, by a large margin in weighting terms.
- Be classifiable. A clear, consistent subject makes it easy to find your audience. An account covering five unrelated topics is genuinely harder to distribute.
- Post when your audience is around, because early engagement compounds.
- Ignore single-post variance. The test-audience draw varies; some good posts get unlucky rounds.
- Do not chase mechanics you cannot verify. Most algorithm folklore describes symptoms rather than mechanisms.