The blog post title should have also included “for Chrome*” (i.e., "... offline document editing for Chrome* ...")
“Offline document editingOfficial Google Enterprise Blog: Get things done anytime, anywhere: Announcing offline document editing and Google Drive for iOS
No internet connection? No big deal. With offline editing, you can create and edit Google documents and leave comments. Any changes you make will be automatically synced when you get back online.
You can enable offline editing from the gear icon in Google Drive and find more detailed instructions for getting set up in the Help Center. Note that you’ll need the latest versions of Chrome or ChromeOS to edit offline. We’re also working hard to make offline editing for spreadsheets and presentations available in the future.”