Ads are great, Google says, except for the 3.2 billion bad ones

The number of ads that tried to harvest personal information, distribute malware or otherwise violate Google policies doubled from 2016 to 2017.

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Google headquarters in Mountain View, California

Google headquarters in Mountain View, California.

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Online ads enable all sorts of free services online, including search and social networks and the article you're reading now, but Google is working harder than ever to keep the bad ones at bay.

"In 2017, we took down more than 3.2 billion ads that violated our advertising policies," said Scott Spencer, Google's director of sustainable ads, in a blog post Tuesday. That's an average of 100 per second, and an increase from 1.7 billion removals of bad ads in 2016. In addition, Google banished 320,000 online publishers for violations like showing Google-supplied ads alongside inappropriate or controversial content, he said.

It would be nice if we didn't have to coin the term "malvertising" to describe online ads that actually try to implant malicious software on our computers, but the world of online ads has a pretty big dark underbelly. Google's financial lifeblood is advertising, so it's got a strong incentive to keep ads clean. And we need it -- with bots manipulating election debates on Facebook , conspiracy theorists publishing YouTube videos and trolls unleashing vitriol on Twitter, we've already got plenty of toxic material on the web to worry about.

Bad ad practices that Google worked to stop include phishing scams to fool you into revealing personal information like passwords and account numbers, links to sites that try to trick you into installing malware , ads placed along news stories copied from legitimate news sites and violations of some Google ad privacy requirements.

There's still work to be done, though.

"Google can't keep up with the whack-a-mole," tweeted David Barnard, a developer of the free, ad-supported Weather Atlas app for iPhones . He complained specifically of ads that try to fool people into installing a new user profile that opens up a new inbox that bad actors can use to send ads, phishing attempts or other problematic emails. Google's AdMob pays the best among mobile ad networks, but he's seriously considering ditching it, he said.

Google's ad policing does operate at a massive scale. Among ad actions Google took in 2017:

  • Blocked 79 million ads for trying to send us to malware-infected websites.
  • Removed 48 million ads trying to get us to install software we don't want.
  • Suspended 7,000 users of Google's AdWords ad-placement service for scams like diet pill sales and weight-loss programs reached by misleading ads that look like eye-catching news headlines.
  • Banished 320,000 publishers from the AdWords network for violating ad policies.
  • Blacklisted 700,000 mobile apps for violating ad policies.
  • Blocked 12,000 websites with content scraped from legitimate websites, up from 10,000 in 2016.
  • Added policies to curtail ads relating to financially risky moves with cryptocurrencies, foreign exchanges and other unregulated or speculative areas.

Google has to come up with new policies, not just enforce the existing ones, Spencer said. "As consumer trends evolve, as our methods to protect the open web get better, so do online scams."

First published March 13, 9:04 p.m. PT.
Update, 9:39 p.m.: Adds comment from developer David Barnard.