Level 10
QUESTION to be answered and justified: what is the most effective adblocker extension?

This weekend I finished a project for my study , before delivering it on Tuesday (tomorrow) I would like to share my findings with this forum. Please don’t hesitate to post your opinion or experiences.
  • This project is an exercise in finding and analyzing field data. With so much data available on the internet, it is easy to find proof for nearly any hypothesis or assumption. The existence of troll and click farms and option to advertise politically tinted ideas on social media makes it hard to determine whether something is true or not.
  • The research question (what is the best adblocker) is chosen as a topic because it resembles the context of shady discussion on the internet:
  • Most people don’t understand underlaying technology (so can’t recognize fake from real information)
  • most people don’t really care about privacy (so they won’t dig into the issue themselves)
  • when asked explicitly most people to be “against” advertisements and trackers
  • when explained most people prefer free (with ads) over paid (without ads)
  • there is an active community against ads and a powerful business industry in favor of ads
Trick information our teacher is an IT-specialist who has sold his IT-business and now teaches for fun a few days per week uses his spare/free time to study philosophy. After he introduced the topic he explicitly stated some questions: what is more effective “less is more” or “brute force”, “data driven” or “community gathered”.

Which extensions to evaluate?
Community powered and brute force, refer to the syntax based blockers AddBlockPlus and uBlockOrigin which mostly use (bottom-up) community based blacklist (e.g. Easylist, Fanboy etc). uBo and ABP both offer syntax to block or hide HTML and CSS (stylesheets) elements. uBO tops this with redirect options and javascript (scriptlet) injections and its own dynamic filtering.
Data driven and less is more are represented by Disconnect and Ghostery. Both Disconnect and Ghostery use small (top-down) defined blocklist. Privacy Possum uses behavioral monitoring to discover trackers and uses a small black/grey/whitelist. Latest Ghostery also discovers unlisted trackers using behavioral analysis.

Which extension is the most effective?
This answer is always related to the websites which are used to test the effectiveness against. So there is no objective answer to that. When you read tests of Gorhill uB0 comes out as best, when you read tests of Adguard, adguard is best, et cetera. By choosing which websites are used to test the effectiveness of an adblocker, one can manipulate the results. So best test / study I could find is block_me_if_you_can which is performed by SBA-research.org an organization related to respected Austrian universities and used 100.000 websites from Alexa top 200.000 which did not require log-in or were 'walled'in any other way. https://www.sba-research.org/wp-content/uploads/publications/block_me_if_you_can.pdf

The winners are Ghostery and uBlockOrigin according to this study


Note 1: study is from April 2017 where uBO version 1.7 was tested. uBO now also blocks and redirect analytics and tagmanagers, so current uBo should block more analytics and tagmanagers (light and dark green category in the uBO column).
Note 2: this score was obtained after Privacy badger was trained with 1000 websites. Latest version of Privacy Badger seems to block more trackers out of the box).
Note 3: When you look at Gorhill’s own research (link), uBlockOrigin in very easy mode (similar to AdblockPlus with acceptable ads disabled) roughly blocks half of the thord-party request compared to uBO in default mode (easy mode).

Less is more when you go with the flow (browse mainstream websites).
At first sight it seems that smaller blacklist (Disconnect, Ghostery, Privacy badger) are more effective than large blacklist (ADBlockPlus and uBlockOrigin).
Member Windows_Security always stated that only a limited number of advertisement and tracking networks exist (because it takes money and resources to develop such a platform). This study seems to back Windows_Security claim
study said:
We found that the great majority of third-party services belongs to a relatively small number of large Internet players
Big is beautiful, when you wander to websites using longtail tracking technology
Ironically this 80-20 rule of the Pareto principle keeps alive smaller advertising and tracking companies, because the adblock extensions block the large players.
study said:
Our results indicate that smaller tracking companies are able to avoid attention from blocking tools and thus persist regardless of the presence of tracker-blocking extensions.
When breaking down the effectiveness of large (bottom-up community) based blocklist versus small (expert top-down) blocklist, it shows that uBlockOrigin is more effective against smaller tracking companies (seen only at less than 20 websites in the Alexa top 200.000). uBO has out of the box, more block rules than any other adblocker tested in this research.


All pigs are equal but some pigs are more equal
All extensions were tested on default values, except Ghostery which they had enabled blocking of all trackers (current default only Advertising, Analytics and Adult ads). This is disappointing in this test, when you test AdBlocking extensions on their capibilities, these should all be tested under the same conditions. So this study might has given an competitive advantage to Ghostery by testing it on tweaked settings. Important notice: when using Ghostery be sure to open settings and click on OPT-in/OPT-out and disable all opt-ins. For better protection it might be a good idea to block social trackers also (Ghostery allows trackers on own websites, so it allows facebook trackers on facebook website).

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Level 10
PROJECT QUESTION: What is the most effective AdBlocker?

Strictly spoken (effective), the answer would be Disconnect. Disconnect scored best after Ghostery. Disconnect and uBlockOrigin both scored the lowest in website breakage as Ghostery in the study. Also they both were the easiest of CPU and memory.

Looking at the future of consumer profiling and tracking, advertisers are starting to use content delivery networks more and more. This makes it easier to change the links and scripts which trigger the tracking and harder for humans to define block rules which allow the content and block the advertisements. In combination with stateless fingerprinting it will be harder in to keep up with advertising technology by user defined rules. to deal with adblock wall's and other thresholds set by advertising networks, the features of adblockers become increasingly advanced.

1. How many adblock users write their own ABP-rules?
2. Hom many have managed to write rules using CSS features?
3. Hoq many of you have know how to use scriptlets features?

So (assuming very little members answer that they write advanced rules themselves) the future way forward iseems to be using some kind of automated blocking mechanisms with behavioral detection or machine learning.

In two studies, scientist used machine learning to determine advertisements on websites. The initial models looked promising, but after training them with the Easylist blocklist they actually performed worse (lost 40 to 80 percent of their probably bad, probably good determination succes rate). So anti-adblocking with machine learning may not be around the corner yet.

So my conclusion is that (with current state of technology) the best mechanismes for automatic blocking of advertisements are based on heuristics and data gathering. This would declare Privacy Badger and Ghostery to the best future proof alternatives.

So I tested Privacy Badger and Ghostery (on Chrome) against each other. It seemed that Ghostery was more effective in finding unlisted trackers. Ghstery found an unlisted tracker (Ster.nl) on the Dutch news website of NOS.nl. This unlisted tracker was determined by behavioral monitoring of Ghostery. Ghostery succesfully blocked the bumper (leading) ads in videos also (which were missed by Privacy badger, Disconnect, ABP and uBO in default). Same thing happened when surfing to commercial news website NU.nl. Ghostery found three unlisted trackers (video player, content delivery network and the website itself) and again managed to BLOCK in video advertisements while PLAYING all videos without delay.

When taking the future of adblocking in mind: the winner should be Ghostery.

4. Have I overlooked an angle which could influence the answer?
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Level 10
Typo errors in post 2 with the questions (I am not allowed to edit that post anymore).

What is the most effective adblock extension: strictly/literally answering that question

What is the most effective adblock extension: taking future advertisement practice and technology into account
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Level 10
I expected to have atleast adguard (extension) in the comparison instead of adblock plus :D
From all mainstream blocklist based AdBlockers, Adguard has the most advanced block rule syntax (besided ABP, CSS, Scriplet injection, it also has its own advanced rules). When tested out of the box as extension (not installed application) it is not better than uBlockOrigin, because its advanced STEALTH features are set to OFF. Based on number of users it is third behind Adblock and uBlockOrigin. So Adguard is a powerhouse with most of its power options not used by its users and disabled by its developers. ??? It is like buying an four wheel drive power truck and only using it as two wheel drive on tarmac roads or buying a sports car with fast quick shift six gear flippers and only driving it below 150 kilomter using its lower four gears.

Trick question are you writing Adguard rules using its own powerful advanced syntax? Have you enabled the STEALTH feature in the extension?
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ForgottenSeer 823865

I use Adguard For Windows with integration mode for the extension (both all stealth enabled) on all my machines except the Linux one (obviously) and its filters are good enough so it doesn't required me to create rules.


Level 7
Trick question are you writing Adguard rules using its own powerful advanced syntax? Have you enabled the STEALTH feature in the extension?
Using the desktop windows version with Stealth features enabled and additional adguard filter lists added.
Never really had the need to learn to write rules. In my years of usage I can only remember very few times I saw ads.


Level 49
Great thread!

Paragraph #2 "Which extensions to evaluate?" lists Privacy Possum but there is no further mention of it later on. Presumably this was a typo and you meant Privacy Badger.

Any reason you didn't include Privacy Possum? Both of these extensions are billed as anti-trackers and not adblockers, but they do block some ads.

Is testing PB and the others in your test comparing apples to oranges?
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Level 25
Malware Tester
Does Ghostery's behavioral monitoring relies on third party cookies? Because I block all third party cookies in my browser and Privacy Badger is actually useless in this scenario which makes sense. Is it the same for Ghostery's behavioral analysis?


Level 10
Re: Adguard

Adguard is a special, it serves as a general purpose adblock extenstion and they maintain their own blocklists. Prerequisite of custom blocklist that it must contain [Adblock Plus 2.0] at the start, otherwise it returns an error (uBlockOrigin is less picky). Both AdBlockPlus and uBlockOrigin don't maintain own blocklists, so Adguard super advanced features are probably only intended to use by their own blocklist maintainers.

Re: Privacy Possum
The project is an exercise in finding the correct data on the internet. I simply don't have test results of Privacy Possum from an established an well recognized research or testing organization. The nice thing about Privacy Possum that it does not block scripts (or third-party requests). When you use a general purpose adblocker (e.g. ABP or uBO) those two extensions nicely complement each other. AdGuard partly overlaps Privacy Possum when you enable stealth option. Privacy Badger also overlaps with Privacy Possum.


Level 23
Member Windows_Security always stated that only a limited number of advertisement and tracking networks exist (because it takes money and resources to develop such a platform). This study seems to back Windows_Security claim
Good thread.

I'd really like to hear Windows_Security's thoughts on this thread.

You both live in the Netherlands.... all of you know each other. Just go knock on his door and ask him to join this conversation. :);)


Really good discussion.

Testing ad-blockers at default settings is much like testing AVs at default settings. Sometimes the results could be very different for us MT types.

But default settings is still is the best basis for testing -- just understanding the limitations.

I can't prove it... but I think uBO at advanced settings is hard to beat. There is SO much that can be done..

I'll take another look at Ghostery. I tried it years ago and was not impressed. But everything changes...


Level 49
Does Ghostery's behavioral monitoring relies on third party cookies? Because I block all third party cookies in my browser and Privacy Badger is actually useless in this scenario which makes sense. Is it the same for Ghostery's behavioral analysis?
Very good question!

I can't prove it... but I think uBO at advanced settings is hard to beat. There is SO much that can be done..
Quite true, as discussed in other threads. It can function as a virtual browser firewall.



Level 27
Content Creator
Ublock origin is so easy to go with, unless youre geek looking for something called optimal setup

Ublock origin on default settings + annoyance filters = for family members, wont break anything
Ublock origin on medium mode = for me, few runs & done

Unless they break ublock origin for firefox, really cant see swapping to other adblockers

About privacy possum....anyone still using trace?


Level 25
Malware Tester

I have to allow cookies to be able to see the video's, so can't test whether Ghostery's functionality to find unlisted trackers is based on cookies.


Be sure to opt-out by disabling all opt-ins. I am testing it also now
Cookies are allowed but third party cookies are blocked which shouldn't be a problem.
I just tested myself the website you mentioned. Videos are playing fine in this website with all third party cookies blocked and the tracker you mentioned = ster.nl is also already in EasyList and blocked by uBlock Origin.
ster 2.png