Darren Herman of Mozilla:
For users with no browsing history (typically a new installation), they will see Directory Tiles offering an updated, interactive design and suggesting useful sites. A separate feature, Enhanced Tiles, will improve upon the existing new tab page experience for users who already have a history in their browser.
Tiles provides Mozilla (including our local communities) new ways to interact with and communicate with our users. (If you’ve been using a pre-release Firefox build, you might have seen promotions for Citizenfour, a documentary about Edward Snowden and the NSA, appearing in your new tab in the past few weeks.)
Tiles also offers Mozilla new partnership opportunities with advertisers and publishers all while respecting and protecting our users. These sponsorships serve several important goals simultaneously by balancing the benefits to users of improved experience, control and choice, with sustainability for Mozilla.
Translation: “We know these ads are gross, but being forever dependent on Google is worse for us. Also, we’ve just found out that it’s really difficult to make money while giving away for free our software and its source code. Also, check out this ad for a movie about the NSA being creepy as shit while we collect your browser history to tailor ads to you.”