Questgivers (WoW)  

Questgivers are NPCs who can initiate a quest. You can identify a questgiver by having a symbol over their head, usually a gold exclamation mark.

List of various symbols:

• Gold exclamation mark - this person has a quest for you now.
• Gold question mark - you are performing a quest for this person and need to report back to them.
• Silver exclamation mark - this person will have a quest for you in a few levels.
• Silver question mark - you are performing a quest for this person that isn't done yet.
• Blue exclamation mark - this person has a Repeatable Quest available.

Note that starting with version 2.3, these symbols also appear on the minimap when you approach a questgiver.