AT&T Inc. (T), Verizon Communications Inc. (VZ), and Johnson & Johnson (JNJ) have decided to suspend non-search advertising on Alphabet Inc. (GOOG) subsidiary Google's platforms. The news was first reported by the Times newspaper last night.

"We are deeply concerned that our ads may have appeared alongside YouTube content promoting terrorism and hate," said At&T in an emailed statement sent to news outlets. "Until Google can ensure this won’t happen again, we are removing our ads from Google’s non-search platforms."

Johnson and Johnson will "pause all YouTube digital advertising globally to ensure our product advertising does not appear on channels that promote offensive content" and Verizon, the fifth-largest U.S. advertiser, has launched an investigation into the issue after pulling its ads.

Google has promised to revamp its ad policies after prominent advertisers threatened to pull out ads from its network. "In the coming days and months, we’re introducing new tools for advertisers to more easily and consistently manage where their ads appear across YouTube and the web," wrote Philipp Schindler, the company's chief business officer in a blog post on the company's website. The tools will provide more control to brands advertising in Google's ecosystem and help ensure that they have more control over where their advertisements are shown or placed.

For example, the Mountain View company plans to introduce controls at the account level that will help set default exclusion for websites or content against which advertisers do not want to display their ads. Similarly, the company has also tweaked its default setting for ads to adhere to a higher level of brand safety. Google has also changed its definition of hate speech to include demeaning and humiliating references towards groups. As an example, the company told Bloomberg that its new definition of hate speech could affect websites "that talk about how women shouldn't learn math or belong in the kitchen."

Google's move comes after several prominent businesses and clients for its advertising solutions pulled ads off its site when the company could not reassure them that their ads would not be placed against content that was inappropriate. Google uses algorithms or programmatic advertising to place ads based on user interests. Big brands and advertising agencies are irked at the incorrect placement of ads that can sometimes result from this. (See also: Facebook, Google to Continue Digital Ad Domination: eMarketer.)

For example, French company Havas, which is the world's sixth largest marketing services group and spends approximately $620 million annually on advertising, pulled its ads off Google and its video platform YouTube last month. A spate of British businesses, including the U.K. government and publishing houses, have also followed suit. In an interview with the Guardian, the U.K. executive director of Havas said that its stance would remain until Google delivers the standards that Havas expects. For its part, Google said that there was "a small number of inappropriately monetized videos and content."

Along with Facebook, Inc. (FB), Google dominates the digital ad markets. As of last year, both companies together accounted for 57% of total digital ad spend. They are expected to continue their domination in the years to come. However, the juggernauts may come under a cloud if they do not take the steps necessary to correct some persistent problems. For example, online publications have highlighted the companies' role in disseminating fake news as well as surfacing questionable content as search results. (See also: Google and Facebook Take Steps to Combat Fake News.)

Sir Martin Sorrell, founder of WPP, the world's largest marketing services group, said that Google and Facebook have the same responsibilities as media companies. "They cannot masquerade as technology companies, particularly when they place advertisements," he told The Guardian. (See also: Google and Facebook Run 57% of All Digital Advertising Worldwide.)

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