Google: Chrome Apps Must Work Offline By End Of Year
Chrome apps are easy to use, but you might have an issue or two with your sin the near future. Google has changed their apps program for Chrome a touch recently, blocking all apps downloaded outside of the Web Store. Now the company is depreciating legacy packaged apps, which might be what you're using when you open up a Chrome app.
A packaged app are those apps that sit in your tray on Windows or OS X, and operate independently of a Chrome browser window. They can run offline, and even open up in their own window. It was Chrome's first move toward a true desktop experience, as Google was encouraging Developers to create packaged apps. Now they're getting serious about it.
Google has stopped being nice about packaged apps, and are asking any Developers who have them to play ball. Legacy packaged apps will no longer be accepted to the Web Store, and those which don't adhere to the new offline-or-die guidelines will likely see issues during operation. If a Developer doesn't want to make their packaged app work with the new guidelines, they will need to make theirs a web app or extension for Chrome.
Google is currently not accepting any new legacy packaged apps in the Web Store, and will start removing them in December of this year. Those already in the Web Store can be updated and supported into June of next year, but will need to be migrated before then to avoid service disruption.
Source: Google