In a blog post, Mozilla's vice president of Firefox Johnathan Nightingale wrote:
A few months ago Darren posted about some experiments we wanted to do with the new tab page. It didn’t go over well. A lot of our community found the language hard to decipher, and worried that we were going to turn Firefox into a mess of logos sold to the highest bidder; without user control, without user benefit.
That’s not going to happen. That’s not who we are at Mozilla.
While it appears as though this plan was foiled by strong user feedback the company hinted that we may still see some new changes. Nightingale added that Mozilla will still be experimenting with other features in the Firefox new tab page in its pre-release channels.
According to the posting the company plans to test a mix of their own sites and other useful sites on the Web as well as potentially adding in a few layout changes. Nightingale suggested that these tests are,"purely to understand what our users find helpful and what our users ignore or disable." Stating that for now at least these tests are not about revenue and none will be collected. He did however leave the door open to future revenue generation through "sponsorship" which may come down the road.