How to Trend on Twitter (X): What the Published Code Now Shows

Learning how to trend on Twitter, now X, still comes down to three things working together: content the ranking model reads as relevant to a specific audience, people who react to it quickly, and a topic other people can actually join. What changed this year is that you no longer have to guess at the first one. X publishes the code that ranks the For You feed, and since 13 August 2026 it publishes the scoring weights with it.

That matters because most advice about how to trend on Twitter is still built on numbers nobody checked. This guide covers what the published system actually does, how X decides what trends, what hashtags are still for, what paid promotion costs, and how to get your X presence found in Google and Bing. For UK and Irish businesses that would rather hand it over, ProfileTree’s social media marketing team runs organic strategy, content and channel management for SMEs across Belfast, Northern Ireland and the UK.

What Has Changed Since Our Last Update

Four things are new or newly confirmed since this guide was last revised in August.

• The weights are public. The 13 August 2026 release added the configuration parameters that combine predicted actions into a single ranking score. Our earlier note that the key weights stayed redacted is now out of date.
• X corrected how people were reading them. On 14 August, xAI added comments to the code because commentators were misreading the numbers. More on that below, because the misreading is everywhere.
• Mutual follows carry a large, documented boost. A change rolled out in July 2026 adds weight to posts from accounts you follow back. X published the full before-and-after as a worked example.
• The four-weekly update cadence has slipped. As of 17 September 2026, the newest entry in the repository’s Latest Updates section is dated 14 August 2026. Treat the cadence as a stated intention rather than a schedule you can plan around.

How the X Algorithm Decides What Trends

Two separate systems are in play, and most accounts optimise for one and ignore the other. Vertical search covers the platform itself: the search bar, the Explore tab and the For You feed. Global search covers how Google and Bing index your profile and posts, which is the same discipline behind search engine optimisation for a website.

On the trends themselves, X’s own Trends FAQ is unambiguous. Trends are chosen by an algorithm and are tailored by default to who you follow, your interests and your location. The system deliberately favours topics that are popular right now over topics that have been popular for a while. Volume is only one input: X states plainly that the number of posts about a topic is just one of the factors used to rank and determine trends.

One line in that FAQ is worth pinning to the wall before you plan a campaign. Trends and hashtags are grouped algorithmically when they relate to the same topic, so #MondayMotivation and #MotivationMonday may both be represented by a single trend. Variant spellings do not necessarily split your volume the way older guides assume, though they still split what a human reader recognises.

What the Published Code Now Shows

X publishes the For You recommendation system at xai-org/x-algorithm on GitHub. Posts arrive from two places: an in-network source holding recent posts from accounts you follow, and out-of-network sources that find posts from accounts you do not. Both sets are ranked by the same model, which reads your recent engagement history and predicts, for each post, how likely you are to take each of roughly two dozen actions on it. Those predictions are then combined into one score.

These are the published default values from that scoring configuration, taken from the worked example X released with the July change.

Two caveats belong with that table rather than after it. First, these are published defaults, kept in step with production values by an automated job, and X runs experiments that change them for slices of traffic. Second, and more important, the weights multiply your predicted probability of taking an action. They do not multiply raw engagement counts. xAI added that clarification to the code itself on 14 August, specifically because people were dividing one weight by another and concluding things like “one report cancels out 468 likes”. That arithmetic is wrong, and any guide repeating it is telling you something the code’s own authors have publicly corrected.

Three adjustments then run after the weighted sum, and each has a practical edge for a business account:

• Author diversity. Each post after an author’s first is multiplied by a decaying factor, down to a floor. Posting seven times in a day does not give you seven full-strength chances in the same feed.
• Out-of-network discount. Posts from accounts the viewer does not follow are scored below the equivalent in-network post, as are replies and reposts from accounts they do follow.
• New-author boost. Posts from authors with impressions below a threshold are lifted toward a target position. A genuinely new account is not starting from zero.

Why Mutual Follows Now Matter More Than Follower Count

The clearest recent change is the bidirectional follow boost. Where you and another account follow each other, the weight on the predicted reply for that account’s original posts is increased. X tested values of 5, 10, 15 and 20 from 10 July 2026, rolled 20 out broadly on 13 July, then cut it to 15 on 24 July after feedback that World Cup discussion from unfollowed accounts was being squeezed out.

The boost applies to original posts only. Replies and reposts from the same mutual follow do not get it. For a regional business account, that reframes the follower question: twenty local suppliers, customers and trade contacts who follow you back are worth more distribution than two thousand one-way followers, and following people back is now a distribution decision rather than a courtesy.

It also demonstrates something worth remembering whenever you read a confident number about the X algorithm. That weight changed twice in fourteen days.

What X Still Does Not Publish

The repository is not complete, and X says so. The prompts used by its content-understanding classifiers are withheld, as are some of the rules that apply visibility labels, on the stated grounds that publishing them would make the anti-abuse systems easier to game. In place of that code, X points people to Under the Hood, a transparency tool at x.com/i/under_the_hood that reports the visibility-affecting labels applied to an account and its posts. It is still a pilot with limited availability, and it is the first thing to check if your posts stopped reaching anyone.

Trending Rules That Block Your Content

Ranking decides the order. A separate system decides whether a post can be shown at all, and it answers one of three ways: allow it, show it behind an interstitial, or drop it. Profanity, adult references and anything breaching the community guidelines will stop a topic trending regardless of engagement volume, as will hatred based on race, ethnicity, national origin, sexual orientation, gender identity, religious affiliation, age, disability or disease.

Some rules only drop a post when it reaches someone who does not follow the author, which is precisely the audience a trending attempt needs. The same post stays visible to your existing followers, so an account can look healthy from the inside while reaching nobody new. Build compliant content into the plan from day one.

How to Check What Is Trending Before You Post

Open the Explore tab, then set a Trends location in settings to see a specific market such as the United Kingdom or Ireland rather than a personalised list. X detects millions of trends daily and shows you a small fraction based on topics you follow, your recent activity, your shared interests with similar accounts and your location, so the list you see is not the list your customer sees. Checking a tag first tells you whether a conversation is crowded, fading or wide open.

Explore also carries Grok-generated summaries explaining why a topic is trending. Use them to get oriented quickly, then verify before you post: those summaries describe what people on X are saying, which is not the same as what happened.

Build the Following That Makes Trending Possible

You need an engaged audience before anything can trend, and the mechanics above explain why a small responsive following beats a large passive one. Speed of reaction feeds the predictions; dormant followers from two years ago do not.

Replies deserve particular attention. Replies and reposts from accounts the viewer does not follow are filtered out of out-of-network candidates entirely, so replying to a large account rarely puts you in front of strangers the way it did five years ago. Replies on your own posts are still the highest-weighted engagement in the table, so the value of a reply is the conversation it starts under your post, not the visibility of the reply itself.

Post Frequency, Timing and Video

Two to four considered posts a day works better than seven filler ones, because author diversity decay discounts your later posts in the same feed and near-identical posts are spread out by a separate diversity reranker. UK audiences tend to engage most between 6:00 and 9:00 in the morning and between 16:00 and 19:00, but check your own analytics rather than trusting a generic window, because regional accounts often break the pattern.

Posts carrying visual elements outperform text-only content, and short-form video under 60 seconds holds attention best, which is where properly produced video earns its budget. Upload it natively, add captions, and put the key term in the first ten seconds, because the content-understanding layer reads on-screen text and speech as well as your post copy.

Profile Optimisation

Your profile is your X homepage, and both the ranking system and human visitors judge it. Use a high-resolution logo or headshot. Write a bio stating what you do, who you serve and where you operate, with keywords included naturally: “Digital marketing agency in Belfast specialising in SEO, web design and AI implementation for UK SMEs” does that in one line. Add a specific location rather than just “UK”, and link to your website with a clean URL.

“Many UK SMEs treat social media profiles as separate entities,” says Ciaran Connolly, founder of ProfileTree. “The most successful businesses integrate their X presence throughout their digital strategy, using each platform to reinforce and amplify the others. Your X profile should be discoverable everywhere your business appears online.”

Promote the profile consistently too. Add social buttons to your website, include your X handle in email signatures, and cross-promote key threads on LinkedIn.

Choose Topics That Can Actually Trend

Your existing followers, and especially your mutual follows, see your content before the wider platform does. Choose topics your current audience already reacts to rather than topics you wish they cared about. Review replies, shares and click-throughs rather than likes, since likes are the cheapest signal a user can give and the scoring reflects that.

A topic also needs to be broad enough for people outside your follower base to adopt. #UKSMEGrowth invites wider participation than #ProfileTreeClients ever could, because the second belongs to one brand.

Local specificity frequently beats broad volume for UK and Irish accounts. “Northern Ireland digital transformation” can produce more meaningful engagement than a generic “digital transformation” post despite lower search volume, and because trends are calculated per location, regional trending inside Belfast, Dublin or Manchester is far more achievable than a national trend. For a business selling to a regional market, it is also worth more.

Hashtags: What They Still Do in 2026

Anyone researching how to trend on Twitter tends to focus hardest on hashtag mechanics, which is where the advice has aged worst. X’s position on tags has moved twice. In December 2024 Elon Musk told users to stop using them on the grounds that the system no longer needs them, and from 27 June 2025 hashtags were banned from ads on X altogether. The ranking model reads your text directly, so a tag is no longer how the system works out what your post is about.

What a hashtag still does is group a conversation people can find and join, which is exactly what a trend is made of. Treat it as the name of the conversation, not as a reach lever.

How Many Hashtags Per Post

X’s own guidance recommends no more than two per post. That is the number to work to. Stacking more looks like spam to readers and gives the ranking model nothing it did not already have from your copy. Put the primary tag inside a sentence where it reads naturally, and leave any second tag to the end.

Character Count and Word Limits

Capitalise the first letter of each word so the tag is readable: #ContentMarketingStrategy is far easier to parse than #contentmarketingstrategy, for screen readers as well as people. Keep it short and to two words at most, since a long tag is hard to recall and retype. Twenty characters is a sensible ceiling, and not an arbitrary one: X’s Trend Takeover ad specification caps a promoted trend hashtag at 20 characters. Say it aloud, and if it is awkward to say it will be awkward to share.

Consistency still helps, though for a human reason rather than an algorithmic one. X groups related tags into a single trend, so a variant will not usually strand your volume in a separate bucket, but people who see three spellings of your campaign will remember none of them.

Execution and Seeding

Once topic and tag are set, execution turns a plan into a trend. The candidate pool holds nothing older than 48 hours, so an attempt has a two-day window at the outside, and realistically the first few hours decide it.

Pre-Trend Content Seeding

Before the attempt, post several times introducing your topic and tag so followers have context and something to engage with immediately. Discuss aspects of the tag without explicitly asking for engagement, and vary where it sits in the post. Invite people to take part by direct message and email, giving advance notice, and pay particular attention to accounts that follow you back. Start at least a month out, because the tag needs recognition inside your network before it can travel beyond it.

Sustaining the Conversation

Conversation beats volume. Ask questions that invite replies and answer properly rather than with thanks, since low-content replies add little and the model is predicting whether a real exchange follows. Give people a reason to use the tag: useful information, a message worth repeating, or a prize worth entering for. Keep contest rules simple and the prize relevant. For live events, post actively through the first two hours and tag speakers and attendees.

When to Move On

Because the system favours what is popular now, most trends last a day or two. If nothing has happened inside the first day, organic traction is unlikely without paid support. Treat a failed attempt as data: look at which posts drew replies and which times worked, then apply that next time. A tag that gains traction in Northern Ireland or one UK city without registering nationally still counts if you sell locally.

Paying to Trend: What Trend Takeover Costs

Paid promotion is the fastest answer to how to trend on Twitter for a business with budget behind a launch. The format once called Promoted Trends is now Trend Takeover, which places a branded hashtag at the top of the trending section in Explore and across timelines, marked as promoted.

What It Costs in 2026

Twenty-four-hour Trend Takeover packages start at around $200,000 for tier-one markets including the United Kingdom, with regional markets such as India, Brazil and Southeast Asia starting between $25,000 and $50,000. Other 2026 format guides put takeover placements in a $150,000 to $250,000-plus per day band. Any five-figure daily figure you see quoted for a UK trend is describing a different market or an out-of-date rate card.

The specification is worth knowing even if the price rules it out, because it shows how X itself formats a trend: one hashtag of 20 characters maximum, a short trend description, and three to six promoted posts eligible to appear against the trending tag, supplied as image, GIF or MP4.

Promoted Posts: The SME Alternative

Promoting individual posts to defined audiences costs far less and keeps control of targeting, spend and duration. A £50 daily budget wins enough auctions to learn from, with around £500 per campaign a reasonable test. X CPMs generally sit between $5 and $12 in Western markets, below Facebook and well below LinkedIn, which makes testing cheap relative to other platforms. Note that hashtags are not permitted in ad copy on X, so the tag does the work organically while the ads carry the message.

Check the site can absorb the traffic before you spend. Paid promotion accelerates content that already performs; it does not rescue a weak account.

X SEO: Getting Found Beyond the Platform

X posts rank in Google and Bing, so your profile behaves like a page that search engines crawl and index. This keeps paying off months after a campaign ends.

Profile, Cards, Links and Video

Your bio doubles as a meta description, and your pinned post carries extra weight for indexing. X Cards control how shared links appear, and most UK businesses get the best result from the Summary Card with Large Image, which depends on the correct meta tags being present on the page you link to. External links suppress reach, so add commentary before the link or put it in a reply. Upload video natively rather than linking out, add captions because many people watch without sound, and hook viewers in the first three seconds.

Geographic Targeting and Measurement

Include a specific location in your profile, tag relevant UK locations on posts, and use tags such as #BelfastBusiness or #NorthernIrelandTech. This works much like local SEO on Google, where consistent details plus local engagement build regional authority. X Analytics tracks impressions, engagement rate, profile visits and follower growth; check them weekly, and treat an engagement rate above 2% as a strong reception. Track enquiries that originate from X rather than impressions, because enquiries are the only number that reaches your P&L.

Feeding Grok and AI Answers

Grok draws on live X data to answer questions and to summarise trends, so your posts can become source material for AI-generated answers. Structure information as definitive, checkable statements with numbers attached rather than hedged opinion. A thread that builds a complete argument on one topic gives a model more to work with than an isolated post. Keeping terminology consistent across your posts, your site and your published content is what lets an answer engine corroborate a claim across sources instead of treating it as a one-off, and the same logic applies to cross-promotion between owned channels.

Getting Your X Strategy Right

Start with the profile: keywords in the bio, a specific location, an optimised pinned post. Then follow back the accounts that matter to your business, because mutual follows now carry documented weight. Then audit honestly: are you posting consistently, and does your content invite conversation or only announce things?

Pick one relevant topic, plan a full campaign around it, and run that campaign properly rather than spreading effort across several. Seed the tag for a month, post into the window your own analytics supports, reply to everyone who engages, and measure enquiries rather than impressions. Learning how to trend on Twitter well enough to produce business results, rather than a screenshot for the team channel, comes down to that sequence repeated until it works.

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