German court overturns ruling that ad blockers are not illegal, Mozilla warns that extensions may be inconvenient

Ad blockers, which remove ads from websites and apps to improve browsing experience, have repeatedly been accused of being illegal because they reduce revenue for operators who rely on advertising. In a lawsuit brought by a German publisher against AdBlock Plus, a type of ad blocker, the court ruled in 2018 that ad blockers were legal , but the German Supreme Court overturned the ruling and ordered a retrial of the case.

'Ad Blocking is Not Piracy' Decision Overturned By Top German Court * TorrentFreak
https://torrentfreak.com/ad-blocking-is-not-piracy-decision-overturned-by-top-german-court-250819/

Mozilla warns Germany could soon declare ad blockers illegal
https://www.bleepingcomputer.com/news/legal/mozilla-warns-germany-could-soon-declare-ad-blockers-illegal/

Adblock Plus is an ad blocker available as a browser extension and smartphone app, developed by Eyeo GmbH, a Cologne, Germany-based company. German publisher Axel Springer filed a lawsuit in 2015 alleging that Adblock Plus was interfering with its business model.

Axel Springer initially sued, arguing that ad blockers constituted unfair competition law. However, in a 2018 ruling, the German Federal Supreme Court disagreed, stating that because it was up to individual users whether or not to use the software, no laws had been broken and unfair competition had been perpetrated.

Adblock Plus, the leading ad blocking app, is being sued for being illegal, but the Supreme Court has ruled it legal - GIGAZINE

Axel Springer subsequently requested a retrial, arguing that Adblock Plus 'infringes copyright' by modifying website code and allowing users to access legally protected content. Eyeo countered, arguing that Adblock Plus simply blocks certain code from being loaded, without actually rewriting it. As a result, in 2022 the Hamburg Regional Court ruled again that the ad blocker was illegal, finding that 'there was no evidence of unauthorized copying or reworking of computer programs as defined by copyright law.'

Ad blocking not a copyright infringement ruled - GIGAZINE

Axel Springer appealed again, but lost again in 2023. However, Axel Springer appealed to the German Federal Supreme Court (BGH) , which overturned the High Court's decision, stating that a retrial was required for further technical and legal investigation.

Axel Springer's new argument is based on the 'Software Protection Provision' in Section 69a (3) of the German Copyright Act, which states that a computer program is protected by copyright if it 'constitutes an individual work of authorship insofar as it is the author's own intellectual creation.' Under copyright law, a computer program is treated as a work of authorship, and the author has the exclusive right to reproduce, distribute, and make the program available to the public.

Axel Springer argued that the software used to create its media is eligible for copyright protection, and that 'Adblock Plus's blocking or manipulation of website code in users' browsers constitutes an infringement of its exclusive rights of modification and reproduction.' The Supreme Court responded by pointing out that the High Court's decision 'reached its decision without establishing any significant technical foundation.'

At the time of writing, the court has only granted a retrial that includes technical aspects. It is unclear whether ad blockers are deemed illegal, and it is unclear which parts of copyright law or which technical aspects of websites will determine the outcome of the lawsuit.

However, if the lawsuit concludes that a website's HTML/CSS is a protected computer program and that interfering with it constitutes illegal copying or modification, extensions and other similar technologies are likely to be significantly affected. Daniel Naser, senior product advisor at Mozilla, which operates the Firefox browser, warned, 'There are many reasons why users want to modify web pages using their browser or browser extensions, beyond ad blocking. The technical background to the German legal dispute could also affect various browser extensions, hindering user choice.'

The new legal process is likely to take years to reach a final conclusion, and Nazer said that extension developers may choose to limit the functionality of their tools for the time being to avoid the risk of future financial losses, potentially limiting browser users' freedom of choice.