Why ‘Bad’ Ads Appear on ‘Good’ Websites – A Computer Scientist Explains

Yves here. Since readers sometimes get ads that seem at odds with our content, and are perplexed, it seemed this explainer would be helpful. However, at least some years ago, I was amused by how often we’d get campaigns from big banks when we were very critical of their business practices and regularly calling for top execs to be prosecuted. We’d reassure readers that that financial firms paying us to run content opposed to their interest was a form of accidental penance.

By Eric Zeng, PhD Candidate in Computer Science & Engineering, University of Washington. Originally published at The Conversation

Sketchy ads, like those for miracle weight loss pills and suspicious-looking software, sometimes appear on legitimate, well-regarded websites. It turns out that most websites don’t actually decide who gets to show ads to their viewers. Instead, most sites outsource this task to a complex network of advertising tech companies that do the work of figuring out which ads are shown to each particular person.

The online ad ecosystem is largely built around “programmatic advertising,” a system for placing advertisements from millions of advertisers on millions of websites. The system uses computers to automate bidding by advertisers on available ad spaces, often with transactions occurring faster than would be possible manually.

Programmatic advertising is a powerful tool that allows advertisers to target and reach people on a huge range of websites. As a doctoral student in computer science, I study how malicious online advertisers take advantage of this system and use online ads to spread scams or malware to millions of people. This means that online advertising companies have a big responsibility to prevent harmful ads from reaching users, but they sometimes fall short.

Programmatic Advertising, Explained

The modern online advertising marketplace is meant to solve one problem: match the high volume of advertisements with the large number of ad spaces. The websites want to keep their ad spaces full and at the best prices, and the advertisers want to target their ads to relevant sites and users.

Rather than each website and advertiser pairing up to run ads together, advertisers work with demand-side platforms, tech companies that let advertisers buy ads. Websites work with supply-side platforms, tech companies that pay sites to put ads on their page. These companies handle the details of figuring out which websites and users should be matched with specific ads.

Most of the time, ad tech companies decide which ads to show through a real-time bidding auction. Whenever a person loads a website, and the website has a space for an ad, the website’s supply-side platform will request bids for ads from demand-side platforms through an auction system called an ad exchange. The demand-side platform will decide which ad in their inventory best targets the particular user, based on any information they’ve collected about the user’s interests and web history from tracking users’ browsing, and then submit a bid. The winner of this auction gets to place their ad in front of the user. This all happens in an instant.

When you see an ad on a web page, behind the scenes an ad network has just automatically conducted an auction to decide which advertiser won the right to present their ad to you. Eric Zeng, CC BY-ND

Big players in this marketplace include Google, which runs a supply-side platform, demand-side platform and an exchange. These three components make up an ad network. A variety of smaller companies such as Criteo, Pubmatic, Rubicon and AppNexus also operate in the online advertising market.

This system allows an advertiser to run ads to potentially millions of users, across millions of websites, without needing to know the details of how that happens. And it allows websites to solicit ads from countless potential advertisers without needing to contact or reach an agreement with any of them.

Screening Out Bad Ads: An Imperfect System

Malicious advertisers, like any other advertiser, can take advantage of the scale and reach of programmatic advertising to send scams and links to malware to potentially millions of users on any website.

There are some checks against bad ads at multiple levels. Ad networks, supply-side platforms and demand-side platforms typically have content policies restricting harmful ads. For example, Google Ads has an extensive content policy that forbids illegal and dangerous products, inappropriate and offensive content, and a long list of deceptive techniques, such as phishing, clickbait, false advertising and doctored imagery.

However, other ad networks have less stringent policies. For example, MGID, a native advertising network my colleagues and I examined for a study and found to run many lower-quality ads, has a much shorter content policy that prohibits illegal, offensive and malicious ads, and a single line about “misleading, inaccurate or deceitful information.” Native advertising is designed to imitate the look and feel of the website that it appears on, and is typically responsible for the sketchy looking ads at the bottom of news articles. Another native ad network, content.ad, has no content policy on their website at all.

These political ads from the 2020 election are examples of potentially misleading techniques to get you to click on them. The ad on the left uses Trump’s name and a clickbait headline promising money. The ad in the center claims to be a thank you card for Dr. Fauci but in reality is intended to collect email addresses for political mailing lists. The ad on the right presents itself as an opinion poll, but links to a page selling a product. Screenshots by Eric Zeng

Websites can block specific advertisers and categories of ads. For example, a site could block a particular advertiser that has been running scammy ads on their page, or specific ad networks that have been serving low-quality ads.

However, these policies are only as good as the enforcement. Ad networks typically use a combination of manual content moderators and automated tools to check that each ad campaign complies with their policies. How effective these are is unclear, but a report by ad quality firm Confiant suggests that between 0.14% and 1.29% of ads served by various supply-side platforms in the third quarter of 2020 were low quality.

Malicious advertisers adapt to countermeasures and figure out ways to evade automated or manual auditing of their ads, or exploit gray areas in content policies. For example, in a study my colleagues and I conducted on deceptive political ads during the 2020 U.S. elections, we found many examples of fake political polls, which purported to be public opinion polls but asked for an email address to vote. Voting in the poll signed the user up for political email lists. Despite this deception, ads like these may not have violated Google’s content policies for political content, data collection or misrepresentation, or were simply missed in the review process.

Bad Ads by Design: Native Advertising on News Websites

Lastly, some examples of “bad” ads are intentionally designed to be misleading and deceptive, by both the website and ad network. Native ads are a prime example. They apparently are effective because native advertising companies claim higher clickthrough rates and revenue for sites. Studies have shown that this is likely because users have difficulty telling the difference between native ads and the website’s content.

These are examples of native ads found on news websites. They imitate the look and feel of links to news articles and often contain clickbait, scams and questionable products. Screenshot by Eric Zeng

You may have seen native ads on many news and media websites, including on major sites like CNN, USA Today and Vox. If you scroll to the bottom of a news article, there may be a section called “sponsored content” or “around the web,” containing what look like news articles. However, all of these are paid content. My colleagues and I conducted a study on native advertising on news and misinformation websites and found that these native ads disproportionately contained potentially deceptive and misleading content, such as ads for unregulated health supplements, deceptively written advertorials, investment pitches and content from content farms.

This highlights an unfortunate situation. Even reputable news and media websites are struggling to earn revenue, and turn to running deceptive and misleading ads on their sites to earn more income, despite the risks it poses to their users and the cost to their reputations.

Print Friendly, PDF & Email


  1. aj

    Wish I could share a screenshot because right below the section on Native Ads is an ad that appears to look just like an NC link to an article. If it didn’t have the Sponsored Content box at the top, you wouldn’t be able to tell the difference.

    It has orange bold header followed by a two-line summary just like links on the NC home page.

    1. jefemt

      Mine is showing CBOE VIX Futures. I have trained my eye to ignore that little link. I think it would be fun to sit in a small group, go to a N C simultaneously, and see how differently the AI has pigeonholed each of us. Mr. Fred Rodgers had it right: you ARE special!

      You are THE product!

      AI, Y AI, Y AI-Y AI …

    2. Joe Well

      I have seen this before but I am looking at the site now on a browser that allows ads and I do not see any “native” ads.

      1. Joe Well

        Actually I only see five ads, all static “banner” type, and all very unobtrusive. They’re all retargeting ads for a single site I visit regularly. One next to the naked capitalism logo, two in the side bar, one in the body of the post and one at the very end of the post.

  2. marcel

    What seems to be missing here is that the Content Policy runs both ways.
    As an exemple, a French group ‘Sleeping Giants’ looks at the ads that appear on the websites they target, and then they write to the advertising companies with a text such as: “this website is extreme right and borderline legal. Look at hate speech they publish . Does your company want to be associated with this type of content?”
    And in several instances, the companies reply that they have taken necessary measures to no longer advertise on that website. With the ultimate goal of shutting down the targeted website for lack of revenue.
    So websites can (a bit) select what ads they want to exclude, but advertisers can also select which websites they want to exclude.

    1. Duke of Prunes

      I have heard some internet/media savy people claim that the majority of censorship is driven by advertisers and the companies for which they advertise.

      Why does YouTube de-monitize videos? We’re led believe it is because “they” don’t like the content. In fact (this theory goes), “they” really do not care about the actual content, but they do care about P&G or GM or ATT or “big company X who worries tremendously about their brand image” dropping ad buys because their ads are showing up as sponsors of “inappropriate” content. The act of “de-monitization” isn’t so much about cutting off the “bad actor’s” resources, but rather to protect the platform from irate advertisers. No ads run, no worry about an upset advertiser…. and the revenue flows which, in the end, is all that matters.

  3. Arizona Slim

    Questions: If NC went ad-free, those sketchy ads that hijack phones (like mine) would no longer be a problem. So, could this be an option?

    Yes, we’d have to hit the Tip Jar harder and give more during the annual fundraiser, but why not? Let’s be reader-supported and be the change we wish to see in the world.

    1. Geo

      There are a few issues with this:

      1. Audience supported platforms/media are more financially polarized than just about anything in our economy. A few bring in buckets (or truckloads) of cash while most starve.

      2. While being beholden to advertiser demands can impact news coverage, this system NC uses is basically anonymous (they don’t know who is advertising and even the ads you or I see are different depending on our browsing history and demo targeting) so who advertises has no impact on their journalism. Whereas, audience supported sites are at the whim of their audiences’ tastes. Just look at the clown show that is YouTube news/politics channels for a taste of what type of garbage audiences support versus what they don’t. All it would take is one issue that NC takes a divisive position on for donations to dry up and cripple the site. A mix of ad support and audience donations better frees them up to follow their ideals without being reliant on sentiment from ads or readers. Also, they don’t need to devote weeks to annoying pledge drives like NPR and PBS.

      3. I have an ad blocker that makes the issue mute for me. If ads give your browsing issues you could try that. But, due to financial hardships over the past couple years I’ve disabled it for NC because I can’t donate as much as this site merits considering it’s my regular news source. Hopefully the ad revenue I bring in compensates a bit. Who knows?

      I’m not a fan of ad supported platforms due to censorship. My last film recently launched on one and they had to cut over 15 minutes from the movie to make it “advertiser friendly”. So, if anyone wonders why entertainment seems so homogenous now days, that’s your answer. That said, my film was floundering on rental platforms like Amazon, Apple, Vudu, and Roku. On this new “free” ad supported site it got over 125K views in the first month alone. This made it pretty clear to me that people expect their media to be free now days. Some “top tier” media can get people to pay up but the lower tiers (where the substantive media is mostly found) have to find whatever ways they can to survive.

      I think NC’s hybrid model of anonymous ads and reader donations is ideal in our current media environment. Sort of the best of both worlds.

      That said, I’d totally buy an NC tote bag if they wanted to do pledge drives like NPR!

      1. Yves Smith Post author

        Sadly we don’t have the staff to handle any kind of mailing. I am the only manager person and anything I do on swag is at the expense of posting.

        Operationally there is no way to do it. I can’t even find the bandwidth to send proper e-mail thank yous after the fundraiser.

        Someone did design a series of NC goodies that readers could buy at CafePress (no coffee cups though, that requires a minimum order and they don’t ship them). It wasn’t a money thing, CafePress took pretty much all, we only got a 10% fee. CafePress flushed our designs and I can’t find them :-(

    2. Joe Well

      My NC experience is ad-free because I use the Brave browser (except now, to see the ads).

      I use Brave not to avoid ads but because of all the tracking Javascript and potential security vulnerabilities.

      Is that bad? Should I make an effort to visit NC on a standard Chrome browser? Or does the per-user advertising revenue really matter?

  4. Questa Nota

    Online advertising is just one of several insidious intrusions and inconveniences in so-called modern life.
    Travel around the country, or the world, and see how much or how little of life is monetized, commoditized, crapified.
    Ad-blockers help, as does unplugging selectively like a Quiet Weekend or similar non-electronic sojourn.
    Visitors to the US remark at how trivial life has become due to pervasive advertising. Companies push out idiotic ads that long ago ceased to be plausible, pick your faves, or unfaves, all in the name of chasing a buck.
    I look forward to a Quiet Three-Day Weekend, and aside from NC visits, encourage you to as well.
    /end rant /restart life

  5. Paleobotanist

    I can ignore the ordinary ads but what disturbs me are: 1) the buy a concubine ads (used to be from Russia, now all from the Ukraine) and 2) women’s clothing ads that are frankly pornographic (seems to be a way to dodge a filter perhaps?). Over my years, I have known a fair number of these bought concubines, both female and male, and almost all seem to be put thru hell by the guy who controls their papers. This is not a joking or snickering matter. The porn ads besmirch the seriousness of this site and the enormous efforts put into it by Yves, Lambert, and everyone else. They make us look bad to newcomers, including women and religiously inclined people, who are perhaps less represented here, and make us all lose the benefits of their thoughts and considered opinions.

    1. Geo

      I don’t intend this disparagingly but the ads we each see reflect our own browsing history and demographic targeting of us. Personally, almost every ad I see on NC is for some fashion brand, patio furniture, or cameras/electronics. Due to my work these are the things I research and/or buy the most.

      Not that I don’t have my lascivious tastes in online browsing but I use a different, more secure browser for that stuff. :)

      1. paleobotanist

        I don’t have any lascivious tastes in my on-line browsing actually. In this one area, they are targeting the wrong person.

        1. Geo

          In that case it must be the the highest bidder for general advertising space. If you want cleaner ads, visit a few apparel shopping websites. Those things will litter your computer with trackers and all you will get are ads for whatever tshirts and shoes you happened to click on until the end of time.

          1. fjallstrom

            On new units I have noticed a pattern with “concubine ads” on pages that write about politics that include Russia and/or Ukraine. I have figured that lacking a browser history the ad-tech goes for content, in a very AI-stupid way. So articles about Russia/Ukriaine gives concubine ads and articles about finance gives stock tips ads.

            Then I ususally install an ad-blocker.

  6. Angie Neer

    My favorite instance of algo-driven advertising on NC was when Lambert’s commentary was surrounded by ads from a sporting-goods store—for waders. I treasure the screen shot of that.

  7. eg

    I get my daily NC fix on an iPad. The “Reader” function and/or judicious sizing of the screen such that the comments fill it horizontally reduces my exposure to ads sufficiently that I don’t generally have the slightest idea what they might be flogging …

  8. orlbucfan

    I ignore the ads. At least, they don’t screech at you like the boob tube ones do. I remember the dreaded days before the “mute” button. Probably a good reason why I don’t really care about TV.

    1. Yves Smith Post author

      We have way fewer ads than our ad service wants us to have. We have no popups and no video autoplay ads, which it turns out means no video because the whole point apparently is the autoplay, the non-autoplay ones pay worse than normal ads.

      So we are leaving money on the table to improve your user experience!

      1. Larry

        And we thank you immensely for this! There are sites that have ruined themselves with auto-play ads. Particularly on mobile, it can destroy the experience entirely.

  9. c_heale

    What I find amusing is that I decide to buy a product, and when I’ve decided on the model I want I get it secondhand (usually), and then the majority of the ads for the next few months are about the same product. The advertising algorithms seem pretty poor.

    What is disturbing, that more recently there have been a couple of occasions when I’ve mentioned (speaking only) something to a friend, while I have my phone in my hand or pocket, and then when I get back home, there are ads about said something, or in one case a youtube recommendation. These are things that I’ve only mentioned to that one other person and have no real interest in. I use android by the way.

    1. notabanker

      Yes, Android listens to you. I started noticing it a few years ago. When I first mentioned it to my 20something kids, they laughed at my ignorance.

Comments are closed.