Google announced two important features for Google Drive users at I/O event. One is Now you can edit and create Google Documents offline. and another one is now Google Drive available for iOS devices.With the Drive app, you can open PDFs, photos, videos, documents and anything else stored in your Drive while you're on the go from your iPhone, iPad or iPod touch running iOS 5.0+ .
Google Docs Offline :
No internet connection with Offline editing tool you can edit and create Google documents and also able to leave comments on offline mode. If you make any changes and created new documents with offline editing tool, it will be automatically synced when you get online back.
To enable the offline tool just go to the gear icon from Google Drive. Then select "Setup Docs Offline" from drop down menu (detailed instruction here). The important thing is Chrome browser should be a latest versions on your machine.
Google Drive for iOS :
Google announced another important feature is Google Drive now available for iOS devices such as iPhone, iPad and iPod touch.
Download from App store - Drive for iOS