NPR's Aarti Shahani covers the new DoubleVerify solution to prevent advertisers from inadvertently supporting fake news websites.

""If there was an airplane accident in Florida you don't want to be promoting discount airfare or vacation travel in the context of that article," says Wayne Gattinella, CEO of DoubleVerify. He helps to build these filters.

Gattinella says his customers, the brands that advertise, recently requested that he build a new filter to blacklist news that is fake and/or extremist — rightwing or leftwing sites that use sensational headlines and have little to no real reporting. He says nearly half of the hundreds of sites he's identified in this category did not exist at the beginning of this year. They're newer, and according to his estimates, traffic to these sites has nearly doubled in the last month alone."

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