Uncovering and explaining how our digital world is changing — and changing us.

Google is giving advertisers more information about where their ads display on YouTube after marketers pulled business because ads were funding videos of hate speech and terrorism.

GroupM, the world’s largest media buying firm, said it has signed up a company to help ensure that its clients’ ads run against appropriate content. GroupM clients include L'oreal cosmetics, HSBC Bank, Lloyds Banking Group, supermarket chain Tesco and retailer Marks and Spencer. Those five advertisers publicly announced earlier this month they had suspended ads on YouTube in the U.K.

A source close to the situation said Google supplied GroupM with the complete list of YouTube channels in Google’s so-called Preferred advertising program. The list is not publicly available, but other Google clients may also request it. Clients advertising on these channels otherwise receive reports from Google about where ads have already run, but without the list cannot know for certain where their ads could potentially run.

Google Preferred includes higher-quality videos or YouTube channels with large followings.

GroupM is using video analytics company OpenSlate to analyze the content of channels on the list GroupM obtained. This will allow GroupM to determine ahead of time where ads from their clients should run. OpenSlate will earn a commission when GroupM's clients use the monitoring service, according to GroupM.

The media buyer said Google already made similar third-party analysis possible in other areas, but that this was the first time it was possible with preferred content.

OpenSlate does not have a contract with Google or special access to the company’s data, Google confirmed.

Last month, Google removed a popular YouTube creator from its preferred advertising program over issues with hate speech in the creator’s videos. The Wall Street Journal found that Felix Kjellberg, known as PewDiePie, had posted several anti-Semitic videos. Disney subsidiary Maker Studios cut ties with Kjellberg following the discovery.

With 53 million subscribers, PewDiePie’s channel was one of the most popular on YouTube and was considered “brand safe” until the Journal pointed out the inappropriate content. The revelation highlighted the risk of social video content for brands seeking to advertise.

Update: This post has been updated to include more details about information Google gave GroupM and to clarify OpenSlate’s relationship with GroupM and Google.

Sign up for the newsletter Recode Daily Email (required) By signing up, you agree to our Privacy Notice and European users agree to the data transfer policy. Subscribe