Related Clues:

• FYI medium
• ''Didn't you get the ___?''
• Any letter from A to G
• Brief bit of correspondence
• Observe carefully
• It may stick around after the office closes
• Third of a triad
• Twitter message
• "Rockin' Robin" refrain word
• Piano key
• Do, re, or mi
• 'You didn't get the ___?'
• Student's permission slip
• Post a modern status update
• Use Twitter