GMAIL today has released some new features! 11 total will eventually be here!
The ones on the way that I find very cool...
You can set an expiration date on an email to someone so that it disappears from their inbox on that date
Nudging will remind you to respond to messages
& Assistive Unsubscribe will help you see what newsletters in your inbox that you never look at and suggest to you to unsubscribe. You know... all those newsletters you didn't actually sign up for but flood your inbox. Check out the dates to see when these features land (CNET)