Make software, or make platforms, or marketplaces (and how are marketplaces related to platforms), or some other kind of hub?
All, maybe, like Amazon; or Google, somewhat, though Steve Yegge famously ranted that Google's platform appreciation doesn't run very deep (certainly not as deep as Amazon's).
Why platforms? Well, the platform-maker is the facilitator, the one that lets everyone else do everything: the platform-maker doesn't have to make everything, because everyone else will. As Steve argued, the priority of platforms is a logical consequence of the decentralization of the Internet.
As another Steve (Jobs) showed, though, nobody wants to develop on a less-than-awesome platform, and everybody wants to develop on the best. So the platform-maker needs to understand, and the process of software development, really, really well.
Mozilla does understand software development. But however awesome their product, their company is smaller than their competitors (Apple, Microsoft, Google). So Mozilla can 'do everything' far less than the other big players in the browser scene.
Solution for the software developer that can't do everything? Make the platform, or the marketplace, or at any rate the hub for others' work.
So yesterday Mozilla launched its new Apps Developer Community, promising:
Notice the 'web standards and open technologies' emphasis (which the intro video, on the announcement page, also pushes strongly). Mozilla isn't trying to take from competitors; they're trying to become the go-to place to publish open ecosystem apps for any device. This isn't a platform in the technical sense. But it does try to do for Mozilla what the App Store and AWS are both accomplishing, in different ways: bring web developers to Mozilla for any web development project whatsoever.
One of the coolest features is the app manifest -- just what the name implies, though more fully explained in the documentation.
With no danger of tie-in, because apps in Mozilla's developer community will be completely standards-based. Mozilla's documentation is geared toward helping, or friendly-ly pushing, developers to integrate HTML5 technologies in ways they might not have considered before joining the Mozilla's developer community.