X’s transparency tools ‘an utter disappointment’ - Apple, TikTok, and LinkedIn not much better

None of the ad transparency tools created by 11 of the world's largest tech companies to aid watchdogs in monitoring advertising are operating as effectively as needed, leaving voters worldwide vulnerable to disinformation and manipulation, according to Mozilla and CheckFirst research released today.

These tools, mandated by the European Union’s Digital Services Act (DSA), Article 39, would enable researchers to monitor a wide range of issues such as election disinformation by monitoring ad content, targeting criteria, and reach. In March, the EU adopted additional transparency rules focused on political advertising, to rein in disinformation on elections, referendums, or legislative processes. This regulation sets out further requirements for the ad repositories, but these changes won’t kick in until after this June’s EU elections. Because global tech companies often implement changes across their platforms to comply with international regulations, the EU regulations could have an outsized effect in non-EU countries with major elections this year — like the United States, Mexico, and India — leading to a ripple effect of how advertising is managed and monitored on these platforms worldwide.

The study — Full Disclosure: Stress-testing tech platforms' ad repositories — found that the repositories are plagued by missing data, bugs, shoddy features, and unacceptable shortfalls.

Mozilla and CheckFirst investigated AliExpress, Apple App Store, Bing, Booking.com, Alphabet’s Google Search & YouTube, LinkedIn, Meta, Pinterest, Snapchat, TikTok, X, and Zalando. Researchers tested the transparency tools using over 20 parameters, including functionality, data accessibility, and accuracy. Parameters are informed by the DSA and also Mozilla’s own ad library guidelines.

The repositories often leave a lot of uncertainty about who is behind an ad — and the system can easily be gamed. Meta discloses the beneficiary and the payer, while most platforms disclose the “Advertiser” or “Sponsor” without further context. TikTok, Bing, and Google, for instance, include the registered location of the party paying for the ad. The repositories would leave roughly half the world's population estimated to be voting in elections in 2024 uncertain about who is behind the advertising content they consume.

“X’s transparency tools are an utter disappointment,” said Claire Pershan, EU Advocacy Lead at Mozilla. Its repository offers no filtering and sorting capabilities; ads can only be accessed through a cumbersome CSV export file; the content of ads is not disclosed (only a URL to the ads), and there are gaps in targeting parameters and recipient data. And searching for historical content is nearly impossible. All this may be why the European Commission has included X’s ad repository in its formal proceedings against the platform under the DSA.

Apple, LinkedIn, and TikTok fared moderately better, but only by comparison — they also have big gaps in data and functionality. Most tools were hindered by search rate limits, poor sorting and filtering features, limited accessibility, and more.

A table showing the effectiveness of platfroms' ad libraries

Says Pershan: “Ad transparency tools are essential for platform accountability — a first line of defense, like smoke detectors. But our research shows most of the world’s largest platforms are not offering up functionally useful ad repositories. The current batch of tools exist, yes — but in some cases, that’s about all that can be said about them.”

Ad transparency tools are essential for platform accountability — a first line of defense, like smoke detectors. But our research shows most of the world’s largest platforms are not offering up functionally useful ad repositories. The current batch of tools exist, yes — but in some cases, that’s about all that can be said about them.

Claire Pershan, EU Advocacy Lead, Mozilla

Amaury Lesplingart, Chief Technology Officer and co-founder of CheckFirst, added: “Who pays for ads and how they’re targeted is crucial in helping watchdogs look out for the public interest - whether that's fair elections, public health, or social justice. In short, if you see an ad telling you that climate change is a hoax, you might be interested to know if that ad’s paid for by the fossil fuel industry."

In addition to scoring the tools, Mozilla researchers provide several recommendations to platforms and policymakers. Among them: Platforms should improve search and filtering functionalities, and provide better documentation and help features. And policymakers should require the standardization of APIs across platforms to increase usability and facilitate cross-platform research, and also strengthen requirements around branded content.

Mozilla and CheckFirst researchers also put forward a recommendation for a Standardized Digital Advertising Format (SDAF), a standard for offering a holistic view of digital ad campaigns.

This research complements Mozilla’s other work on 2024 elections, like examining platforms’ election integrity policies and grading synthetic content detection techniques.

Additional Findings

Missing ads. Our accuracy testing found many cases where ads in the user interface were not found in the ad repository. This can limit the usefulness and trustworthiness of the repositories as a transparency tool.

Various degrees of “public accessibility.” There is a spectrum of accessibility for the web repositories and the APIs, considering factors like the need for a login and the need to apply formally: On one end, platforms like Apple and Booking offer access to the web repository and API even without an account. On the opposite end, Snap, and Aliexpress have no APIs at all, at the time of writing.

Search features are lacking. Effective navigation through ad repositories is hampered by the lack of filtering and sorting options. While TikTok offers useful sorting options and Meta and Bing useful filtering options, no VLO studied has both sorting and filtering options.

Paid influencer content or ‘branded content’ remains elusive. Only a handful of the platforms analyzed have a repository for branded or influencer content, even though many allow for influencer content on their services. Previous Mozilla research has found this kind of content is underreported, and this problem appears to persist according to recent research into TikTok by Stiftung Neue Verantwortung.


Press contacts:
Tracy Kariuki: [email protected]

Helena Dea Bala: [email protected]