Google Inbox is an email app by Google for Android, iOS, and Google's Chrome browser (other platforms planned). When the user logs in, Google scans user's gmail for important and similar information. It then presents what it considers the most important parts of the email first and groups similar emails as "Bundles" that are named by type (e.g., "Travel" or "Updates").
More info: http://www.google.com/inbox/
Btw, a new Google Inbox video released today.