Google Inbox

This may be separate from Gmail but what it does is to sort out the emails you receive into respective categories. Perhaps, it is more like some kind of an experiment that you will get in the future, not now as we may probably think that it may be merged with Gmail. If you had already opted for the new Gmail introduced last year, the sorting was already done. At this moment, the feature is in beta phase and invite only so it's not the easy way to get into it.