The chairwoman of Mozilla Foundation, the software firm behind the Firefox internet browser, has hit back at critics to the proposed tile ‘advert’ feature in a blog post.

Mitchell Baker, who played a key role in setting up Mozilla Foundation in 2003 following the collapse of AOL, said:

"When we have ideas about how content might be useful to people, we look at whether there is a revenue possibility, and if that would annoy people or bring something potentially useful. Ads in search turn out to be useful. The gist of the Tiles idea is that we would include something like 9 Tiles on a page, and that 2 or 3 of them would be sponsored — aka ads."

However, Baker reiterated: "These sponsored results/ ads would not have tracking features."

The feature planned by Firefox would see the introduction of sponsored tiles in the ‘new tabs’ page on the browser. Some of these tiles would be favourite web pages or history, but some will be advertisements.

"Why would we include any sponsored results? If the Tiles are useful to people then we’ll generate value. That generates revenue that supports the Mozilla project. So to explicitly address the question of whether we care about generating revenue and sustaining Mozilla’s work, the answer is yes. In fact, many of us feel responsible to do exactly this," said Baker.

Mozilla content services vice president Darren Herman said that the sponsored tiles will be clearly labeled as such, while still leading to content we think users will enjoy.

"We are excited about Directory Tiles because it has inherent value to our users, it aligns with our vision of a better Internet through trust and transparency, and it helps Mozilla become more diversified and sustainable as a project," Herman said.

"While we have not worked out the entire product roadmap, we are beginning to talk to content partners about the opportunity, and plan to start showing Directory Tiles to new Firefox users as soon as we have the user experience right."