Mozilla on Thursday accused Microsoft of forcing its Edge browser down the throats of Windows users through "dark patterns" – design elements geared to push people towards certain decisions.

In [1]a report [PDF] titled, "Over the Edge: How Microsoft's Design Tactics Compromise Free Browser Choice", the public benefit browser org argues that Windows users are encouraged to use Microsoft Edge and deterred from other options.

Mozilla has made similar claims before – notably in its September 2022 [2]"Five Walled Gardens" report and its [3]"Platform Tilt" report last month. Those reports covered wider competitive barriers present in platforms operated by Apple, Google, and Microsoft.

[4]

"Over the Edge" focuses specifically on Microsoft Edge and alleges manipulative design patterns – sometimes referred to as "dark patterns" or "deceptive patterns" – that push people towards a preferred outcome when presented with a choice in a visual interface. Other tech operators, such as Amazon, have also been [5]accused of using dark pattern designs – which persist, despite [6]laws aimed at limiting such trickery.

[7]

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"Windows users everywhere, especially in the rest of the world, continue to have their choices inhibited, overridden and undermined by Microsoft's use of harmful design," Mozilla [9]wrote in a post about its report. "Regulatory action around the world is needed to restore browser choice and competition across all of the major platforms."

The salient regulatory action here is Europe's Digital Markets Act (DMA), a set of rules intended to promote fair competition across the bloc. Mozilla cites the implementation of the DMA – enforcement is set to begin in March – as a reason to hope that the barriers to browser competition will come down.

[10]

"However, even where there is movement in the right direction, improvements have been incomplete and are grudgingly offered only in markets where regulators have forced platform owners to make changes to respect browser choice," the browser biz lamented, citing Apple's decision only to [11]allow alternative browser engines in the EU .

The Register asked Mozilla whether its willingness to challenge competition concerns has increased lately.

"Our position about fair and open competition has not changed," a Mozilla spokesperson replied. "However, there is an increased need to understand and identify some of the technical aspects related to legislation like the DMA which is why we commissioned the independent research."

[12]Brit watchdog thinks Google's tweaked Privacy Sandbox still isn't cricket

[13]Microsoft Edge ignores user wishes, slurps tabs from Chrome without permission

[14]Microsoft's plucky challengers, Bing and Edge, might gain DMA exemptions

[15]Windows 11 unable to escape the shadow of Windows 10

Mozilla's report allows that developers like Microsoft should be able to promote their wares – provided they do so without techniques that cloud users' choices. The nonprofit software house argues that users, without coercion, manipulation, or deception, should be able to: download and install any alternative, legitimate browser; set that browser as their default; and use their chosen browser on an ongoing basis.

The report defines various manipulative interface patterns like "Confirmshaming", "Forced Action", "Visual Interference", and "Disguised Ads."

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As an example of the last, it cites the way that [17]Edge has injected ads for Microsoft's browser into the Chrome download page on Google's website.

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Screenshot from Over the Edge report of Microsoft Edge injected ad during Chrome download – Click to enlarge

Mozilla also condemns the way that Microsoft's Bing search engine injects ads for Edge in response to a search for a rival browser like Safari or Vivaldi.

"The message appears in a non-standard format that we have never observed in any other Bing ad," Mozilla's doc notes, adding that it resembles "the Windows user interface, which the user may further interpret as a marker of authority and legitimacy."

"With this message Microsoft is taking advantage of the trust gained by their custodial role as OS provider and using it to misdirect users, implying that compliance is necessary for security reasons," the report alleges. "A user may reasonably conclude therefore, that this message is some sort of system notification or system warning."

Another pattern the report identifies is called "Obstruction": "In the Windows 11 Settings app, when a user navigates to the 'Default apps' page for a web browser (eg Apps > Default apps > Firefox), they are shown a button at the top of the page allowing them to set that browser as their default. However, after the user clicks this button, many file extensions and link types are left with the previous default unchanged."

The report concludes: "We have found that Microsoft uses a number of harmful designs to influence users into using the Edge browser. In our view, these designs coerce, manipulate, or deceive users and are therefore unjustifiable, with the potential to cause a variety of consumer, society, and market harms. Microsoft should stop using these techniques immediately."

Microsoft did not immediately respond to a request for comment. ®

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[1] https://research.mozilla.org/files/2024/01/Over-the-Edge-Report-January-2024.pdf

[2] https://www.theregister.com/2022/09/23/browsers_mozilla_microsoft_google/

[3] https://www.theregister.com/2024/01/25/mozilla_apple_google_browser_wars/

[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/applications&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2ZbzLXhFYancHB1hCMqptEwAAAII&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0

[5] https://www.theregister.com/2023/06/21/amazon_prime_ftc_lawsuit/

[6] https://www.theregister.com/2020/10/13/california_updates_privacy/

[7] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/applications&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44ZbzLXhFYancHB1hCMqptEwAAAII&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[8] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/applications&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33ZbzLXhFYancHB1hCMqptEwAAAII&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0

[9] https://research.mozilla.org/browser-competition/over-the-edge-the-use-of-design-tactics-to-undermine-browser-choice/

[10] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/applications&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44ZbzLXhFYancHB1hCMqptEwAAAII&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[11] https://www.theregister.com/2024/01/31/web_developers_worry_apple_ios/

[12] https://www.theregister.com/2024/02/01/google_privacy_sandbox_concerns_remain/

[13] https://www.theregister.com/2024/01/30/microsoft_edge_tabs/

[14] https://www.theregister.com/2024/01/24/microsoft_edge_bing_dma/

[15] https://www.theregister.com/2024/01/02/windows_11_unable_to_escape/

[16] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/applications&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33ZbzLXhFYancHB1hCMqptEwAAAII&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0

[17] https://www.theregister.com/2023/02/23/microsoft_edge_banner_chrome/

[18] https://regmedia.co.uk/2024/02/02/edge_dark_pattern.jpg

[19] https://whitepapers.theregister.com/