Mozilla, the company responsible for the Firefox web browser, has said that it will start testing placing adverts inside its software.

Earlier this year, Vice President of content services Darren Herman, outlined the company's plans to trial placing adverts in the page that appears when users open up a new tab.

As Firefox users browse the web this page populates with suggestions based on their most frequently visited sites. Herman suggests that for fresh installs of the browser it could instead be filled with “pre-packaged content”.  

Fans reacted angrily to the suggestion, worried that such a scheme might turn the browser into “a mess of logos sold to the highest bidder”  (in the words of vice president Johnathan Nightingale).

Firefox have since clarified their position, saying that the scheme won’t operate “without user control” or “without user benefit”.

"That's not going to happen. That's not who we are at Mozilla,” wrote Nightingale in a blog post. “But we will experiment.”

“In the coming weeks, we’ll be landing tests on our pre-release channels to see whether we can make things like the new tab page more useful, particularly for fresh installs of Firefox, where we don’t yet have any recommendations to make from your history," said Nightingale.

“We’ll experiment on Firefox across platforms, and we’ll talk about what we learn before anything ships to our release users,” he added.

Firefox enjoys a good reputation online for its readiness to listen to users,  introducing polices such as automatically blocking tracking cookies that place it at odds with advertisers but that please privacy advocates.

The introduction of ‘sponsored tabs’ could anger these same fans but might prove necessary to maintain the browser’s competitiveness.

Mozilla is a non-profit company and is slowly losing its market share to Google's Chrome and Microsoft's Internet Explorer – browsers backed by corporate titans with deep pockets.

Neither of these companies place adverts in their browsers but do instead make their own search engine (Google and Bing) the default choice for customers.