Ad-Filtering Dev Summit 2023: recap

Content blocking may be but a drop in the vast ocean that is web technology, but we're happy that AdGuard happens to be part of it. What we cherish the most about our field of choice is, of course, the community. We have strong ties with the developers of other ad blockers and browsers, with filter maintainers and privacy researchers. Of course, there may be competition at times, but in the end we all know that we're working towards the common goal — making the Web safer for everyone.

The highlight of our collaboration is the annual Ad Filtering Dev Summit, where we all gather together to talk about what we've achieved over the last year and what challenges lie ahead.

We've written about all the past Summits in our blog, you can read about the previous one here.

This year, the AFDS 2023 took place in Amsterdam over two days, and it was packed with pressing topics, prominent speakers, and captivating talks. We'll cover them all and try to strike a balance between detail and brevity, so you can pick and watch the talks that interest you the most. You can also watch the entire event online and we would appreciate if you share your feedback with us and tag us on social media.

We will cover the topics in no particular order, and then we will list all the remaining talks that did not fit into any specific category. Let’s begin.


It probably won't surprise you to learn that AI is starting to affect the ad blocking industry, just like everything else. The initial craze over chatbots may have died down a bit, and you have a small chance of going through your day without hearing about ChatGPT, but people are still using them more and more for just about every task imaginable. And where there are lots of online users, there are ads. Some chatbots are honest and label the ad links in their replies, others sneak an ad into their replies so you wouldn't even notice it.

However, the relative scope of such ads is rather small for now. Blocking 'regular' ads remains by far the main task of current ad blockers, and it will stay that way for a while, but the day is not far off when you won't be able to call yourself a content blocker unless you can deal with chatbot ads.

Vladimir Zhelvis and Natalia Sokolova from AdGuard devoted their talk to modern LLMs (large language models), ways they can be exploited to deliver ads to users, and possible methods of blocking ads delivered that way.

Vladimir Zhelvis and Natalia Sokolova on using LLMs for user tracking and ad delivery

Dr. Humera Noor Minhas and Parinitha Hirehal from eyeo are frequent speakers at AFDS, and they never fail to deliver a great talk. This time, they chose to speak about how AI impacts ad filtering as a whole now and what will change in the future.

Dr. Humera Noor Minhas & Parinitha Hirehal on the impact AI has on ad filtering

Filter lists

One of the highlights of this year's Summit was the increase in the number of filter maintainers in attendance. They got much more speaking time than usual, and it was long overdue. Many casual ad blocker users may not realize that it's filters that actually block ads, and content blockers themselves can't magically distinguish ads and trackers from the actual content of the web page. And maintaining a filter list is a tedious and never-ending task, so we all better show filter developers some respect!

At AFDS 2023 filter maintainers deservedly got a lot of attention. Most notably, Ryan Brown, Imre Eilertsen, Elena Porubin, Peter Lowe, Dávid Tóta, Andrey Meshkov, and HoJeong Go participated in Filter lists maintainers panel, where they touched upon many different topics related to filter lists and, hopefully, cleared for all the viewers what does it mean to be a filter list maintainer.

Ryan Brown, Imre Eilertsen, Elena Porubin, Peter Lowe, Dávid Tóta, Andrey Meshkov, HoJeong Go on Filter lists maintainers panel

In addition to participating in the filter lists maintainers panel, some of its participants delivered separate talks, which were just as exciting:

However, this is not the end of filter lists story at AFDS 2023. We decided to group some of the filter list-related talks into a separate section.

Filter lists ecosystem

At their core, filter lists are what the name implies — lists of rules, each of the rules basically a text string. However, simplifying the process of creating a filter into mere meddling with a .txt file is doing its creator an injustice. There's much more work done behind the scenes, not visible to the eye. The 'filter list ecosystem', as we call it, expands rapidly, and there were several excellent talks about it at AFDS 2023.

Dávid Tóta from AdGuard looked back at the evolution of developer tools for filter creators and presented AGLint, a tool that makes it easier to develop filter lists and arms their creators with new, powerful instruments.

Dávid Tóta, talking about the evolution of developer tools for filter lists and presenting AGLint

Sandra Siby, Research Associate at Imperial College London, talked about another thing that could potentially revolutionize the filter development process — automatic detection of website breakages by filters.

Sandra Siby on automatic detection of breakage caused by ad-blocking

A report by Hieu Le, Postdoc at University of Michigan, Ann Arbor & University of California, Irvine, expanded on the topic of automatization as he spoke about the future automatic filter lists generation.

Hieu Le on the future of automatic filter list generation

Right now, both of these automatic tools (especially the tool for website breakage detection) are not production-ready. But when they will be, ad blockers will leap to the entirely new level. We will be able not only to automate filter rules creation but, ultimately to greatly improve the quality of ad blocking — something that the end users will be able to experience first-hand.

Browsers & MV3

Oh, Manifest v3... If you follow our blog or take interest in browser extensions in general, you've certainly heard about it a thousand times already. But just in case you didn't — Manifest v3 is the new proposed browser extension API for Chrome browser, coming to replace its predecessor Manifest v2. To put it simply, it will define what extensions can and what they can not do. It was first announced in 2019 and spurred a major controversy, as it aimed to severely restrict the capabilities of many extensions, including content blockers.

Just as in 2022, MV3 was one of the most-discussed topics at the Summit this year. However, the narrative has changed a bit: the community's view on it was far more positive today than a year or so ago. Not in the least thanks to the common effort by the developers of browsers and browser extensions. Dmitriy Seregin, a software engineer from AdGuard, presented an update on the current state of Manifest v3 at AFDS 2023.

Dmitriy Seregin on how AdGuard adapted its extensions to MV3

A big factor that helped sway the attitude of the ad-blocking community towards Manifest v3 is the willingness of Chrome's developers to take our concerns into consideration. We can see the concrete steps that they take to address them, and this was reflected in the big report presented by a group of Chrome devs at the Summit.

David Li, Devlin Cronin, Oliver Dunk, Patrick Kettner, Chary Chen on what's new in Chrome

For a different perspective on MV3, watch the browser developer panel at AFDS that included developers of Chrome, Firefox, Opera, and Brave browsers. Lots of tricky questions, lots of interesting replies.

Arjan van Leeuwen, Luca Greco, Devlin Cronin, Anton Lazarev on Browser panel

Despite the fact that the Chrome devs spend considerable resources on fixing the MV3, and the dynamic is definitely positive, there are still many questions left. So follow our blog to stay tuned — we will keep you updated on the topic of Manifest v3.

Regulations & legal matters

Content blocking can be a touchy subject, as blocking ads can cost websites and publishers money. For this reason, the legality of ad blocking has been at the forefront of discussion for years, the most famous case being eyeo vs. Axel Springer — we've covered it before.

Key Recke, General Counsel at eyeo GmbH, has told the Summit attendants about the most recent developings of this case. Thankfully, so far so good, but it's too early to celebrate.

Kai Recke on how publishers use copyright claims to control browser configuration

It's not just lawsuits, of course. Natascha Gerlach, Director of Privacy Policy at Centre for Information Policy Leadership, Cornelius Witt, Director Global Public Affairs at eyeo, and Lartease M. Tiffith, Executive Vice President, Public Policy at IAB, talked in lengths about the intricacies of the US and EU regulatory landscapes in the data privacy area.

Natascha Gerlach, Cornelius Witt, Lartease M. Tiffith on the US and EU regulatory landscapes in privacy

Lisette Mei, Data Protection Officer at Piwik PRO, homed in on the new EU-US Data Privacy Framework and its implications.

Lisette Meij on the new EU-US Data Privacy Framework

Privacy research

The Summit has "Ad Filtering" in its name for a reason, but it's not just about blocking ads. Content blocking and privacy protection go hand-in-hand, and AFDS 2023 has showed exactly that. Several speakers chose to talk about various privacy-related topics. Each of them is interesting in its own way:

The talk by Ben Savage from Meta gets a special notion from us. Ben spoke about developing a new standard for calculating conversions in a privacy-friendly manner. Browsers step away from third-party cookies (which is good), but they are looking for a substitute to keep evaluating the effectiveness of ads.

Ben Savage on private ads measurement standards

It's not often that people from "the opposing camp" join the Summit, so we're especially glad to see that AdTech representatives keep users' privacy in mind too.


A few of the talks were devoted to sustainability and the problem of carbon footprint that computers leave. You may be surprised to learn that that this topic, seemingly unrelated to ad blocking, attracted not just one, but several speakers. In reality, when you think of it, blocking ads saves quite a bit of energy!

Sustainability in ad-blocking-related areas is a very real issue, and it is further illustrated by the fact that one of this Summit's few panels was dedicated exactly to this matter.

Terry Taouss, Leigh Freund, Claire Gleeson-Landry, Justin Wohl on prioritizing sustainable media


We'd like to cover every talk, but some were just too specific to put them in the same basket with the others. It doesn't mean that there's something wrong with them! Rather they deserve a special mention from us.

  • Welcome word by Summit moderators and Gertrud Kolb, Chief Technology Officer at eyeo. She spoke about principles of humanism in tech

  • Web Monetization — The 100% Ad Filter by Sabine Schaller, Engineering Lead at Interledger Foundation. Her presentation was dedicated to an innovative way of getting rid of ads while still supporting publishers

  • Beyond Effective Extensions: Automated Testing of SDKs by Agnieszka Czyzewska, Senior Software Development Engineer in Test, eyeo. She shared her team’s experience in maintaining effective tests for the solution which empowers ad filtering extensions


All in all, we believe the Summit was a success. It kept all the good from the previous year and built upon it. We discussed both the "evergreen" topics, such as Manifest v3, and new exciting ones, like AI and sustainability issues. We had a great time and are looking forward to see what the next year's AFDS will bring.

Hope you found this Summit's talks informative and entertaining and share our excitement for the next one!

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