How does Stack Exchange ensure that ads don't deliver a tracking pixel if I have opted out of cookies? Is it impossible for an ad to track me if I have opted out of targeting pixels or could an ad served on Stack Exchange pages accidentally or maliciously ignore my cookie settings and the advertising policy?

If it is possible, how would I detect it and report the violation to the company?

I remembered this old discussion around an offensive ad being displayed and the staff response was:

These ads are absolutely against our policies, we will take this down immediately and remove the advertiser completely. We have actively excluded dozens of categories of ads; this is a case of a bad actor trying to get around the restrictions we have put in place. [...] We are actively working very hard to put better monitoring, flagging, and other controls in place.

This made me wonder if a "bad actor" could ignore policy and just track me anyhow for some period of time before getting caught. Is there technology to ensure advertisers can't get around the restriction on tracking pixels? Can I rely solely on Stack Exchange's promises to not allow these pixels (that are much more difficult to detect than cookies) to be used for ads I view, or do I need to also use other blocking technology? I came across an article on spreadprivacy.com that claims:

Blocking third-party cookies and related mechanisms do partially restrict cross-site trackers (which is a good thing for sure), but the reality is that as long as a tracker is still being loaded in your browser, it can definitely still track you — a bit less easily, but tracking is still tracking, and the most prevalent cross-site trackers (those from Google and Facebook) are certainly still tracking you.

I don't know how web advertising works in detail and, frankly, I don't think I should have to become an expert in it to understand how my browsing activity could be unintentionally leaked to third parties. The cookie policy does very little to help me understand exactly how my information is protected and what I actually need to do to prevent it from being shared, other than trusting that the advertisers who are making money from tracking me will respect my wishes not to be tracked. The Cookie Policy states

In this Policy, we use the term “cookie” to refer both to cookies and similar technologies.

And directs me to more information about managing cookies:

For further information on cookies generally, including how to control and manage them, visit the guidance on cookies published by the UK Information Commissioner’s Office, https://www.aboutcookies.org or https://www.allaboutcookies.org.

but the linked sites only talk about cookies and not "similar technologies". I would like to know what “similar technologies” are in use and how I can detect whether an advertiser on the network is not respecting my preferences.

  • 6
    In the second half of 2019. SE began using a real-time bidding system for ads, in which there wasn't much vetting at all. This system concluded in December 2019. Commented Feb 26 at 22:30
  • 1
    @SonictheAnonymousHedgehog Thanks — I had a vague memory around something like that for content… I’d like to know what the current process is to ensure that ads are complying with the retargeting pixel policy and user consent. settings.
    – ColleenV
    Commented Feb 26 at 23:48


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