It’s always a bit of a shocking event when the lion and the lamb go quietly walking around together like they’re meant to be together. Which is why it’s a bit of a head scratcher to hear that Mozilla — the company that once ticked off the advertising industry by announcing plans to test a patch to block third party cookies by default — will now be displaying ads right from inside its browser.

Last year a top lobbyist from the Interactive Advertising Bureau called Mozilla’s default block on third-party ads a “nuclear strike” on the industry, AdAge points out, but the two groups are certainly a bit friendlier now: Mozilla says in a blog post today that it’ll start selling ads that display right in the Firefox browser… and it made the big reveal at the annual IAB conference.

These ads won’t just pop up or meander alongside whichever page you’re viewing, but when a new user opens a fresh tab in Firefox they’ll see suggestions for pre-packaged content in the “directory tiles.” Before now, those spaces stayed blank until they eventually became populated with things you like and sites you’ve visited over time.

The whole shebang has been dubbed “Directory Tiles,” non-profit Mozilla writes in the post:

Directory Tiles will instead suggest pre-packaged content for first-time users. Some of these tile placements will be from the Mozilla ecosystem, some will be popular websites in a given geographic location, and some will be sponsored content from hand-picked partners to help support Mozilla’s pursuit of our mission. The sponsored tiles will be clearly labeled as such, while still leading to content we think users will enjoy.

Thus far there’s no word on which advertising partners will be jumping in with Mozilla from the start, but the company says it’s looking to date around.

“We are looking to partner with like-minded content owners and creators, such as leading publishers and curators as well as innovative advertising agencies,” a spokesperson told AdAge.

Publisher Transformation with Users at the Center [Mozilla Company Blog]

Mozilla To Sell Ads In Firefox Web Browser [AdAge]

Correction: This story originally stated, incorrectly, that Mozilla had blocked third-party ads by default. According to Mozilla, the organization was testing a patch that blocked third-party cookies, but it was never the default in the main Firefox browser, and it was not the ads themselves that were blocked. Mozilla states that they are continuing to test the patch “as part of a number of proposals to give users more control over their online experience.” We regret the error.