All quest conversations are now based on a custom user interface which includes much more useful information about the conversation, over and above the simple quest description. You are also be able to see quest specifics, possible rewards and each specific quest step.
Introduction (when you first talk to the quest giver; gold exclamation mark):
Uncompleted return (grey question mark):
Completed return (gold question mark):
Confirmation of completion:
Note: some existing quests have not been converted to the new UI yet.