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Some Firefox users noticed over the weekend that the browser listed "sponsored" links in the browser's address bar and on the New Tab page. The links, clearly marked as sponsored by Mozilla, are displayed to a small group of users as part of an experiment.

Word got out about Sponsored Top Sites in October when a bug on Mozilla's official bug tracking website Bugzilla@Mozilla confirmed plans to add a toggle to disable the functionality to the Firefox web browser.

The advertisement appears to have been introduced in Firefox 83, released earlier this week to the Stable channel.

If Sponsored Top Sites sounds like something that you have heard before, you are not mistaken. Mozilla announced in 2014 that it would integrate Sponsored Tiles on the browser's new tab page; the feature was pulled from Firefox at the end of 2015 and Mozilla decided to "focus on content discovery" instead back then.
 
Now, five years later, the feature makes a return under a slightly different name. Sponsored Top Sites may be displayed to Firefox users and Mozilla earns money from user clicks on these links.

Mozilla published a support page that provides additional details on the implementation and its advertising partners. According to the information published on the page, Mozilla is working with adMarketplace and only accepts advertising partners that meet the organization's privacy standards.

Anonymized technical data is sent through a Mozilla-owned proxy service before it is send to the sponsoring partner.
 

Quote:When you click on a sponsored tile, Firefox sends anonymized technical data to our partner through a Mozilla-owned proxy service. This data does not include any personally identifying information and is only shared when you click on a Sponsored Top Site.

How to disable Sponsored Top Sites in Firefox

Mozilla added options to disable Sponsored Top Sites to Firefox's user interface.

Note that the sponsored links displayed in the address bar are the same that you see on the New Tab Page.

Firefox users who see these right now may remove individual top sites in the following way.

1. Hover over the sponsored entry on the New Tab Page.
   
2. Open the menu with a click on the three dots.
   
3. Select Dismiss.
   

It is furthermore possible to disable the feature entirely.
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