Game sites, often featuring ad.txt files but little legitimate content, are also becoming more common.

“A single look reveals it’s just nonsense,” Moss added, noting that thousands of these sites are created weekly and continue to qualify for ad spend, “especially through Google’s Pmax campaigns.”

Traffic going to low-quality domains is never going to be zero, according to an agency executive, speaking anonymously to preserve industry relationships.

“With gen AI it’s just easier to spin up an MFA site,” the executive said.

No easy way to opt-out

Google’s ad ecosystem lacks a dedicated exclusion tool for MFA sites, meaning advertisers must manually block individual sites as they appear, according to the first agency exec.

“There isn’t necessarily a blanket setting to keep you out of that inventory,” the executive noted.

Although advertisers can block partial domains before a campaign launches, the constant emergence of new sites makes it difficult to maintain control, according to a second industry executive.

In 2021, Google rolled out dynamic exclusion lists, enabling advertisers to block placements based on topics like politics or devices such as tablets.

Navigating data overload  

While advertisers have long had access to ad tracking data through the Google API, they needed a certain amount of technical expertise to extract it, like writing custom scripts, said the first executive.

Since March, Google has made this data directly available in its ad ecosystem, simplifying access. However, extracting meaningful insights remains a challenge

“They contain thousands of rows in an Excel spreadsheet, so making it actionable and combing through the volume is more difficult,” the executive said.