Google’s Topics API Chooses Small Publishers

The Sell Sideris a column written by the sell side of the digital media community.


Google recently started testing the Topics API, the latest part of its Chrome Privacy Sandbox. It allows Chrome to determine a handful of topics, such as “Fitness” or “Travel & Transportation,” that represent a user’s interests based on their browsing history. But unlike a third-party cookie, subjects do not identify the user.

On the one hand, the Topics API is a significant improvement over FLoC, the former Privacy Sandbox proposal for ad targeting. But that’s a limited gain on privacy for a bad trade-off in terms of utility and concurrency issues. For one, FLoC had 33,000 topics to choose from, while the Topics API only had 350.

The Topics API proposal also carries two unacceptable risks to the open web. First, it enriches large platforms at the expense of niche or independent sites, especially sites that invest time and skill in covering categories in detail. And second, the Topics API leaks audience information from trustworthy sites to sites that leverage advertisers and ad technology.


Unfair data and income transfers

If a user shows strong interest in #VanLife by browsing sites with specific content about vans and related products, then a manufacturer can effectively target them on a general interest site. Blogs or niche sites have created a valuable target audience with a very specific topic assigned to the user, which YouTube, ESPN, or any other major publisher can then capitalize on.

Meanwhile, someone who visits YouTube and is assigned “entertainment” as a topic returns no value to niche sites. Great sites get all the value without giving any back.

The problem is exacerbated by the fact that Google only assigns each site one or a few potential topics. Someone who visits BuzzFeed and reads a bunch of parenting stories is categorized with a “News” or “Entertainment” topic instead of “Parenting,” because BuzzFeed is primarily a news and entertainment site. Smaller sites would do better with Alternatives to the Topics API which promises better control over their audience data.

A step back on brand safety

Another problem with the Topics API is that when you visit sites with commercially relevant topics – like recipes or product reviews – information about your interests may be Leak to misinformation and other dangerous sitesin the form of topics.

Topics API shares this issue with others advertising technologies that track users from one site to another. But when the browser takes on more of the work of running ad auctions, that shouldn’t mean advertisers have to take a step back on brand safety.

The Topics API will need to enable the same level of validation as today’s ad systems. Otherwise, legitimate publishers will increase the value of low-quality or direct malicious actors in digital media without any ability to investigate or curtail the practice.

Getting closer to the benefits of all parties

Google has published the Topics API proposal on GitHub for public review in the new W3C Private Ad Technology Community Group. Advertising industry stakeholders should participate in the discussion and file any concerns on the Topics GitHub API to address concerns. (CafeMedia has already filed several issues, as well as a suggested change This would help the Topics API treat general-interest and topic-specific sites more fairly.)

Today, the Topics API is just a proposal from Google that needs to go through months of testing and other iterations before becoming a standard. Niche or independent publishers don’t have the time or specific expertise to participate in the development of web standards like large platforms do, so their priorities can often get lost in the process.

Let’s work together as an industry to ensure we find the best possible solution to maintain a free and open web.

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