The world's biggest ad-buying firm has jumped on Google's woes by offering a tool to buy 'safe' YouTube ads

GroupM, the world's biggest ad-buying company, is partnering with a video analytics firm to offer a tool that helps advertisers buy "brand-safe" ads on YouTube.

The launch comes in the wake of dozens of global brands pulling their spending from YouTube and Google after finding their ads appeared next to objectionable content on the video platform or websites the online ad giant monetizes through its ad technology.

WPP-owned GroupM announced Wednesday it is forming a partnership with OpenSlate, which gives YouTube content a score for quality and brand safety and provides reporting on where ads ran.

GroupM says this should help eliminate some of the risks of advertising on a platform where much of the content is user-generated - which can lead to brands appearing next to the types of undesirable videos or articles they wouldn't like to be associated with.

Google explained last week that more than 400 hours of user-generated video are uploaded to YouTube every minute and thousands of websites are added to Google's AdSense network daily, which makes it difficult to police. The company also announced a hiring spree, an update to its policies, and improvements to its advertiser controls in an attempt to mitigate the problem, which one analyst predicted could cost $750 million in lost revenue.

But while Google works to get there, GroupM is jumping on the opportunity to tell its clients that it can protect them from their ads appearing anywhere untoward.

GroupM is finally chipping away at YouTube's walled garden

As Business Insider reported last week, many sources within the advertising industry speculated that advertising agencies may use the furor surrounding the YouTube advertiser boycott as leverage to push for what they really want from Google, including data.

One UK advertising executive speculated that a media agency network could now theoretically say: "If we put [YouTube] inventory through our filter, we will clean it up, make it safe, and make a fortune on the side."

GroupM doesn't appear to be directly "making a fortune" with this product, however. A company spokesperson told Business Insider that while advertisers will have to pay a little more to use the OpenSlate service - just like they would with any other third-party vendor for measurement, verification, or brand safety - GroupM isn't taking a fee or margin from this additional cost.

But indirectly, GroupM is on the cusp of a goldmine.

Google is often accused by the ad industry of being a "walled garden" because it doesn't offer advertisers or agency trading desks the ability to run tracking pixels and cookies on YouTube inventory. Advertisers and agencies want to do that so they can use data from YouTube campaigns to inform what they are doing elsewhere on the web. Agencies are also forced to buy YouTube inventory via Google's DoubleClick Bid Manager, rather than third-party demand-side platforms.

GroupM says its new OpenSlate solution will work across reservation media - including Google Preferred, where brands can pay a premium to only appear amongst the most popular content across its platforms, such as music videos and content created by its YouTube stars - and auction-based inventory bought via AdWords and DoubleClick Bid Manager.

GroupM's clients will also be the first to access OpenSlate's reports about where their ads actually ran when they paid the extra for Google's Preferred service. And GroupM gets that data too.

This in itself is quite a development as some advertising sources who have spoken to Business Insider have expressed concerns about their expensive Google Preferred ads appearing next to lots of kids videos - content that may have amassed millions of views but is unlikely to have been watched by an adult consumer that would be capable of actually buying their products.

Not only that, but with GroupM getting access to reporting data, it may have finally found a means to chip away at that once-solid walled garden.

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