If you run ads or track visitors, you have probably been waiting to hear what Google will do after third-party cookies go away in Chrome. On 25 January 2022, Google gave a big part of the answer. The Google Topics API replaces FLoC, its earlier and much-criticised idea for interest-based ads. Instead of putting you in a hidden group of similar people, Chrome will pick a few broad topics from your recent browsing and share a small number of them with sites and their ad partners.
In this article I explain what Topics is, how it works, why FLoC was dropped, and what it means for your analytics and ad campaigns. I also cover what you can do now, while the details are still being tested.
What Google Announced on 25 January 2022
Google announced Topics in a post by Vinay Goel, Product Director for Privacy Sandbox in Chrome. The post says Topics is a new Privacy Sandbox proposal for interest-based advertising and that it replaces the FLoC proposal.
Privacy Sandbox is Google’s set of proposals for keeping ads working in Chrome without third-party cookies (small files that let ad companies follow you from site to site). Topics is the part that covers “show this person ads based on what they seem to be interested in”.
The main points from the announcement are:
- Your browser works out a handful of topics that best show your interests that week, such as “Fitness” or “Travel & Transportation”.
- Topics are kept for three weeks, then deleted.
- Topics are chosen on your device. Google says no external servers are involved, including Google’s own servers.
- When you visit a site that uses Topics, the browser shares three topics, one from each of the past three weeks, with the site and its ad partners.
- The list of topics is curated to leave out sensitive categories, such as gender or race.
- Chrome is building controls so you can see your topics, remove ones you do not like, or turn the feature off.
Google also said a developer trial of Topics in Chrome is coming soon, with user controls included. Reports around the announcement put that trial by the end of the first quarter of 2022. The final details will depend on feedback and what the trial shows. You can read Google’s announcement of the Topics API for the full wording.
Why FLoC Was Dropped
FLoC stands for Federated Learning of Cohorts. The idea was to group people with similar browsing habits into “cohorts” of thousands of users. A site could ask the browser for your cohort ID and show ads suited to that group.
Google tested FLoC in Chrome in 2021, and the trial ended in July 2021. It ran into problems quickly:
- Fingerprinting risk. Critics said a cohort ID could be one more piece of data used to identify a single person, especially when combined with other browser details.
- Hard to understand. A cohort was just a number. Nobody could easily tell what it meant or what it said about them.
- Sensitive groupings. There was concern that cohorts could reflect sensitive things about people, even if nobody planned it that way.
- Little support. Other browser makers did not commit to it, and some large sites and platforms chose to block it.
Many site owners also added an opt-out header to stop their pages being used for FLoC. In my view, FLoC never had the trust it needed. Something meant to replace cookies cannot work if publishers, browsers and users all push back.
How the Google Topics API Works
Topics is simpler to explain than FLoC, and I think that is on purpose. Here is the flow based on Google’s announcement and the technical explainer published with it.
Step 1: Chrome Labels the Sites You Visit
Chrome uses a classifier (a small model that sorts things into groups) to match the sites you visit to topics. The labels are based on the site’s hostname, for example the domain name, not on the full text of every page you read.
The first list of topics has about 350 entries. Google says humans curated it, and it leaves out sensitive categories. The topics are broad, like fitness, travel or news, not narrow labels about a single product or person.
Step 2: Chrome Picks Your Top Topics Each Week
Each week, Chrome works out your top five topics from your browsing history on that device. This happens locally, on your computer or phone.
To add some privacy noise, the design sometimes returns a random topic instead of a real one. That makes it harder to be sure any single topic truly belongs to you.
Step 3: Sites and Ad Partners Ask for Topics
When you visit a site that uses Topics, the site or its ad partners can ask the browser for your topics. The browser returns up to three topics, one from each of the last three weeks.
There is an important limit here. According to Google’s explainer, a caller only gets a topic if it has seen you on a site about that topic in the past three weeks. So a small ad company that only appears on a few sites will get far less than a big network that appears on many.
Step 4: The Ad Is Chosen
The ad partner uses those topics, plus what it knows about the page you are on (contextual signals), to choose an ad. A visitor on a recipe site whose topics include “Fitness” might see an ad for running shoes rather than a general food ad.
This is still interest-based advertising. But the browser decides what is shared, and it shares much less than a third-party cookie does.
Topics vs FLoC vs Third-Party Cookies
The quickest way to see what changes is to put the three side by side.
| Feature | Third-party cookies | FLoC | Topics |
|---|---|---|---|
| What is shared | A unique ID that follows you across sites | A cohort ID shared by thousands of users | Up to three broad topics, one per week |
| Where it is worked out | Ad company servers | In the browser | In the browser |
| Can people read it? | No | No, it is just a number | Yes, topics are plain labels |
| User controls | Block or clear cookies | Limited | See, remove or turn off topics |
| How long data lasts | Depends on the cookie | Recalculated each week | Three weeks, then deleted |
The big change for me is that a person can actually read their own topics. “Travel” means something to a user. A cohort number does not.
What Topics Means for Tracking and Analytics
First, a point I want to be clear on. Topics is about ad targeting. It is not a replacement for your analytics tool, and it does not track individual visitors for you.
Here is what it does and does not change for measurement:
- Your first-party analytics keeps working. Tools that set cookies on your own domain, like Google Analytics, are not the target of the third-party cookie phase-out.
- Cross-site tracking gets harder. Anything that relies on following one person across many websites will lose ground when third-party cookies go.
- Retargeting and frequency caps will change. Topics gives broad interests, not “this person viewed product X”. Other Privacy Sandbox proposals, such as FLEDGE, are aimed at remarketing.
- Conversion measurement is a separate problem. Google says it is working on separate measurement proposals inside Privacy Sandbox. Topics does not solve attribution.
In my experience, many small businesses rely on third-party cookies more than they realise. The ad platform does it in the background, so it is easy to miss. If you are not sure, ask your ad agency or platform how your audiences and conversions are built today.
What It Means for Advertisers
If you buy display or programmatic ads, Topics will shape how interest targeting works in Chrome once cookies are gone. A few things stand out.
Targeting Will Be Broader
About 350 topics is a short list compared with the detailed audience segments many ad platforms sell today. Expect broad interest groups, not narrow ones. In my opinion, this pushes value back toward good creative, good landing pages and strong contextual placement.
Big Networks May Benefit Most
Because a caller only gets topics it has seen on related sites, ad companies with wide reach will see more topics. That is a fair point to watch as testing goes on.
Nothing Changes Overnight
Topics is a proposal heading into a developer trial. It is not live for normal users yet. Chrome’s current plan, announced in June 2021, is to phase out third-party cookies over a three-month period ending in late 2023. So you have time to test, but not time to ignore it.
What It Means for Publishers and Site Owners
If your site earns money from ads, Topics affects you too. Your pages help build the topics that visitors carry around, and your ad partners may call the API on your pages.
Some practical points:
- A clear site theme helps. Since topics are based on hostnames, a site that clearly covers one subject is easier to label than a site that covers everything.
- Your contextual value goes up. When ads rely less on following people, the subject of your page matters more to buyers.
- Check what your ad partners plan to do. Ask whether they will join the Topics trial and how they will use it.
- Watch for opt-out options. With FLoC, sites could send a header to opt out. If you have a reason to do the same with Topics, keep an eye on the developer documentation as it develops.
I would not change your SEO strategy for Topics. Ranking in Google Search does not depend on whether your site uses it. Your content plan should still follow what searchers need, and on a site that is fast, clear and easy to crawl.
How to Prepare for the Topics API Now
You do not need to write code or change your site today. But a little preparation now will make 2022 and 2023 much easier. This is the order I would follow.
- List where you use third-party cookies. Check your ad tags, retargeting pixels, affiliate tools and embedded widgets. Your browser’s developer tools, or a cookie scanner, can show which cookies come from other domains.
- Strengthen your first-party data. Make sure your own analytics is set up well and that email sign-ups and logged-in areas are tracked. This data is yours and is not affected by the cookie phase-out.
- Set up GA4 if you have not already. Google has said GA4 is designed for a future with or without cookies, and running it now builds history you will want later.
- Talk to your ad partners. Ask them which Privacy Sandbox proposals they plan to test, including Topics and FLEDGE, and how they will report results.
- Test contextual targeting. Run a campaign that targets page topics and keywords instead of audiences. It gives you a baseline for a world with fewer cookies.
- Follow the developer trial. When the trial starts in Chrome, read the release notes and see what your partners learn. Details may change based on feedback.
When I review a site’s tracking, I start with step one. Most people are surprised by how many third-party scripts load on a normal page.
Privacy Questions That Are Still Open
Topics is easier to understand than FLoC, but it is not free of debate. These are the questions I expect people to keep asking during the trial:
- Can topics still help identify people? Even broad labels, combined with other data, add a little more information about a user. Google’s design adds noise and limits who can see what, but testing will show how well that holds up.
- Will other browsers use it? Topics is a Chrome proposal. Safari and Firefox already block many third-party cookies, and they may not adopt it.
- How will regulators view it? Google has made commitments to the UK’s Competition and Markets Authority about how Privacy Sandbox is developed. Regulators will keep a close eye on whether these changes favour Google’s own ad business.
- Will users understand the controls? Controls only help if people find and use them. We will learn more once the controls appear in the trial.
My honest view is that Topics is a better starting point than FLoC. It is simpler, easier to explain to a user, and gives people some control. Whether it works well enough for advertisers is still an open question.
Mistakes to Avoid Right Now
I already see a few wrong ideas going around, so here they are in one place:
- Thinking cookies are gone now. They are not. Chrome still supports third-party cookies, and the current plan ends them in late 2023.
- Assuming Topics replaces analytics. It does not. It only helps choose ads.
- Doing nothing until 2023. Moving tracking and ad setups takes time. Start the audit now while there is no pressure.
- Treating FLoC guides as current. Advice about cohorts and FLoC opt-outs is now out of date. Check that what you read is about Topics.
Conclusion: What the Google Topics API Means for You
The Google Topics API replaces FLoC with a simpler idea. Chrome picks a few broad interests from your browsing each week, keeps them for three weeks, and shares a small number with sites and ad partners. Users get controls to see and remove topics, and sensitive categories are left out.
For most businesses, nothing breaks today. Use this time to find where you rely on third-party cookies, build up your first-party data, and ask your ad partners about their plans. If you want a wider view of the work worth doing on your site this year, start with my list of SEO priorities for 2022.
