Only the big online advertising networks can cut off the lifeblood and reduce the financial incentive to create phony stories. iStock By Knight Kiplinger, Editor Emeritus From Kiplinger's Personal Finance, February 2017 Q. I’m troubled by the proliferation of fake news on the internet. I read that the fabricators of these stories have made millions in ad revenue from Google, Facebook and other online advertising networks, based on the traffic the bogus stories generate. What’s being done to stop this?SEE ALSO: Knight Kiplinger's Money & Ethics Quiz A. Fortunately, a lot is being done—belatedly. Ad revenue is the lifeblood of internet publishing, and fake-news mills—employing writers who dream up and churn out outrageous fiction—have been set up simply to tap into a multibillion-dollar ad market. Their made-up stories (with “click bait” headlines) go viral on social media, shared by thousands of web readers who believe them to be true. This traffic triggers ad placements from automated “programmatic advertising” engines used by Google, Facebook and independent online advertising networks. These companies enable the fake-news boom and generate millions in revenues for themselves. Only they can cut off the lifeblood and reduce the financial incentive to create phony stories. Google says it does not place its marketing clients’ ads on sites that allow violent content, hate speech or pornography, and now it says it will include fake-news sites in its ad ban and also try to keep bogus stories out of its news feeds. Facebook also announced recently it will not place ads on fake-news sites, but gullible Facebook users will still be free to share bogus stories with their friends. SEE ALSO: 10 Things You Must Know About Social Security Meanwhile, large national advertisers—always concerned about projecting a positive image for their brands—are putting pressure on social media companies and online media-buying networks to guarantee that their ads don’t appear on fake-news websites or next to bogus stories. Accomplishing this will require a combination of computerized and human monitoring to identify the fraudulent sites, and it won’t be easy. And remember: Curtailing the ad dollars won’t stop fake news that is created not primarily for financial gain, but for ideological purposes—to inflame partisan passions and influence public opinion. Have a money-and-ethics question you'd like answered in this column? Write to Editor in Chief Knight Kiplinger at email@example.com.