DoubleVerify warns Check My Ads of legal action over defamation claims

Ad verification vendor DoubleVerify has warned advertising watchdog Check My Ads of potential litigation, alleging the organisation made defamatory statements regarding the company’s role in detecting fraudulent online advertising traffic.

The warning comes in the wake of a March report by research firm Adalytics, which claimed that ad verification companies, including DoubleVerify, Integral Ad Science (IAS), and Human Security, failed to adequately detect bot traffic, despite being employed by advertisers to prevent invalid and fraudulent traffic.

Check My Ads, a non-profit advocacy group, has collaborated with Adalytics in recent months, promoting the firm’s findings and raising concerns about ad safety and transparency with US lawmakers.

In a letter sent on Monday, DoubleVerify’s legal counsel Brad Bondi of Paul Hastings LLP accused Check My Ads of defamation, tortious interference, and injurious falsehood. Bondi requested the organisation preserve all records and communications relating to DoubleVerify, the Adalytics report, and any previous publications referencing the company.

Adalytics had previously criticised DoubleVerify in a February report, alleging that advertisements from Fortune 500 brands had appeared on a website known to host child sexual abuse content.

In a public statement issued Wednesday, Check My Ads described the letter as containing “vague accusations of defamation and other misconduct,” while calling the demand for communications preservation “overbroad.” The group argued that such legal action could interfere with constitutionally protected communication with lawmakers and researchers working on matters of public interest.

“Legal demands that chill researchers, silence watchdogs, or disrupt communications with lawmakers do not serve the industry or the public, they only reinforce the need for greater transparency and accountability in the digital advertising ecosystem,” the statement read.

The watchdog added that it would comply with its legal obligations in response to the letter.

The dispute emerges as US lawmakers have increased scrutiny of major ad tech firms, including Google, Amazon, IAS, and DoubleVerify, over concerns they may have profited from advertisements displayed on websites hosting child abuse content.

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