|What a shame this doesn't allow use of superstars. Maybe they'll add it later|
via Gmail Blog by The Gmail Team on 3/14/12
Posted by Craig Prince, Software Engineer
Have you ever sent an important email that you wanted to follow up on, but a couple days later realized you hadn’t? Starting today, you can organize your messages before sending them by starring them or adding a label, making it easy to keep track of your sent messages.
When composing a new message, you can assign labels or star it by using the labels drop-down menu. As you’d expect, recipients of messages organized this way won’t see your labels or stars.