Google is taking a while to release their Google Drive client on to the Linux platform. There are a couple of alternatives that do exist for those who are brave enough to try.
Insync is one of those better alternatives that is still under heavy development. The software allows you to instantaneously sync your Drive contents to and from Ubuntu. In addition, Insync lets you edit your documents offline, quickly generate share links though Nautilus, and alerts you to any changes or errors via an indicator applet.
On the privacy side of things, the company who developed Insync assures us that they do not store anything about you (except token and metadata info on your files). All uploads, edits, and deletions occur natively on your device and are then synced to Google Drive.