In the same week as the debut of Mozilla's new Web-based app store the Mozilla Marketplace, Google is pushing for developers to deliver content to the Chrome Web Store that can be accessed even when users don't have an Internet connection. There is already a new highlighted section of the store for such apps.
However, the experience Google wants to create is a little different than that of Mozilla. It's looking for users to still have their Chrome browser open, even without a persistent online connection. Mozilla's Marketplace delivers apps directly to a computer hard drive so they can be launched from the desktop or Start Menu, without the need to open Firefox.
So both browsers are taking a different approach to figuring out how the undeniable popularity of "app stores" can benefit them. Google also promised that the ability to open and edit Google Docs while offline was coming soon. Of course, this is something that's been in the works for a while. It may seem backwards to talk about companies pushing for offline content in this ever-connected world, but that is the piece of the puzzle they are trying to solve right now.