If you use Mozilla’s nightly Firefox builds you get to see a lot of experimental features that for whatever reason are deemed not to be ready for primetime. Sometimes that means you get to see a cool new feature, but right now it also means that you’ll get a new dose of online advertising through the browser’s new tab page (h/t Emil Protalinski at The Next Web).

Firefox Sponsored Tiles

Firefox’s new tab would contain ad tiles mixed among your favorite sites

When you open a new tab on Firefox you can have it open to a specific page or simply a blank sheet by default, but you can also have it open to a page full of tiles, sites that you’ve visited regularly or recently that Firefox thinks you might want to go back to. But in the recent nightly builds, there are also advertisements included among your favorite websites.

Mozilla has said that advertisements will be clearly labeled as such and that they won’t allow any tracking, so you still keep control of your privacy. There’s also no need for a new sort of ad blocker app, because you can simply change settings and get rid of the tiles altogether, although this means you don’t get the benefit of having a handy list of useful sites a hotkey away.

Aggressive advertising could push users toward Chrome

Since users don’t pay for Firefox, Mozilla has to figure out other ways to bring in money. Its main competitor, Google Inc (NASDAQ:GOOG) Chrome, is pretty open about tracking users and using that information for advertising purposes so this is still one of the most innocuous forms of online advertising you’re likely to face, but the change has some users concerned. Once Mozilla decides that monetizing all the information about online habits it has at its fingertips, more invasive methods of data collection and targeted advertising become more a matter of degree. The odd decision to let some websites (eg Amazon) show up for free and not count them as sponsors doesn’t allay those concerns.

Ironically, the need to bring in more revenue may end up costing Mozilla one of its biggest advantages over Google Inc (NASDAQ:GOOG) Chrome. If people stop believing that the Firefox browser gives them more control over their personal data, then there’s not much reason to avoid the browser that’s more naturally suited to Gmail, Android, and all of Google’s other products.