The firm reveals it will roll out a test showing suggested websites to new Firefox users who do not have a browser history when they open a new tab. The new tab page currently displays nine tiles showing screenshots of websites most regularly visited by users.
No revenues will be taken during the test phase but, if successful, sponsorship will be "the next stage".
In a blog post, Mozilla vice-president Johnathan Nightingale admitted many users were concerned that Firefox will be transformed into a "mess of logos sold to the highest bidder". However, he insisted, "That’s not going to happen. That’s not who we are at Mozilla."
Nightingale said: "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.
"We’ll test a mix of our own sites and other useful sites on the web. We’ll mess with the layout.
"These tests are purely to understand what our users find helpful and what our users ignore or disable – these tests are not about revenue and none will be collected. Sponsorship would be the next stage once we are confident that we can deliver user value.
"We’ll experiment on Firefox across platforms, and we’ll talk about what we learn before anything ships to our release users. And we’ll keep listening for feedback and suggestions to make this work better for you. Because that’s who we are at Mozilla."
Last month, Mozilla boss Brendan Eich stepped down after less than two weeks in the job, following controversy over his views on same-sex marriage.