Google vowed today to “tighten safeguards” to help advertisers avoid inadvertently financing “hateful, offensive and derogatory content.” In addition, YouTube will take “a hard look” at the guidelines that determine “what content is allowed on the platform — not just what content can be monetized.”

The new policy, described in a blog post by Chief Business Officer Philipp Schindler, follows snowballing complaints after The Times of London reported that computer algorithms had linked prominent advertisers’ messages with neo-Nazi and jihadist content.

Last week Havas Group UK joined major brands including Volkswagen, Toyota and Heinz in freezing their spending on Google and YouTube. The Guardian also withdrew its advertising, saying that Google’s AdX ad exchange placed its messages on “YouTube videos of American white nationalists, a hate preacher banned in the UK and a controversial Islamist preacher.”

Schindler apologized for the instances “where brands’ ads appeared on content that was not aligned with their values.” Although Google has “strict policies that define where Google ads should appear … at times we don’t get it right.”

As a result, he says, “starting today” Google will remove ads “more effectively” from “content that is attacking or harassing people based on their race, religion, gender or similar categories.”

In addition, the company will “tighten safeguards to ensure that ads show up only against legitimate creators in our YouTube Partner Program — as opposed to those who impersonate other channels or violate our community guidelines.”

Broadly speaking, buyers will have more opportunities to identify the kinds of sites and videos they want to avoid.

To meet these goals, Google plans to hire “significant numbers of people” and develop “new tools powered by our latest advancements in AI and machine learning to increase our capacity to review questionable content for advertising.”

That should enable the company to avoid problems or “resolve these cases in less than a few hours.”

Pivotal Research Group’s Brian Wieser said Monday that although the problem is “relatively small in absolute terms, for large marketers, any one instance of an
inappropriate brand placement may be enough to seriously harm a brand’s business value.”

The analyst downgraded his stock recommendation for Google’s parent, Alphabet, to “hold.” He believes the disclosures “will have global repercussions as UK marketers potentially adapt their UK policies to other markets and as marketers around the world become more aware of the problem. This should curtail spending slightly from the large agency-serviced brands which probably account for a quarter of spending on Google.”