Yes, Mozilla have launched an online marketplace. But it’s not yet for everyone… especially the faint-hearted. The Firefox Marketplace welcomes early adopters and testers who are using Firefox for Android Aurora.
If you remember, Aurora itself is the highly-experimental Firefox browser for mobiles and tablets on the Android platform. The Marketplace is a showcase and a precursor for the full development of the Firefox OS which is the planned platform for low-end smartphones that will run on web technologies and not full-fledged mobile apps as we know them.
The Firefox Marketplace is still very bare bones. It has a smattering of apps from the likes of Distant Orbit, Jauntly, Todoist, Soundcloud and Twitter. The games category is nicely populated with around 116 games. Payments, ratings, reviews, and other features will be added as the marketplace evolves and support for other platforms also opens up. Please note that The Firefox Marketplace for now is available only with Firefox for Android Aurora.
Source: Mozilla Blog