What it is: In iOS 7, each message in a conversation -- whether it's an SMS, MMS, or an iMessage -- now comes with a timestamp showing the time the message was sent or received.
How to activate it: Swipe from right to left on the messages window. Any sent messages will slide over to reveal the timestamp for each entry, and they will bounce back and hide the timestamp when you let go.
Start a phone call
What it is: Users can start a new voice call or FaceTime session with another person without leaving the Messages app.
How to activate it: Tapping the "Contact" text in the upper-right hand corner of a message window will reveal extra options below. The phone icon starts a new call, the camera icon begins a FaceTime session, and the information icon lets users edit that person's contact entry. Tapping "Done" will hide the controls.