Google announced the further integration of Google Drive and Gmail today, with an update to the latter that lets you view and save files directly to Google Drive without actually having to leave Gmail.
When you receive an email with files attached, you'll see previews of the files at the bottom of the message. When you click them, you'll get full-screen views of the images/documents. You can then read, search or browse through them from Gmail itself.
"You can now also save your attachments directly to Drive simply by clicking the Drive button that appears when you hover over the preview," notes Scott Johnston, director of product management. "Of course, if you prefer to download the attachment to your computer, you can—just click the arrow button."
The feature is rolling out over the course of the next week.
On a side note, Google says that Google Drive has 120 million active users.