Possible Clues:

• 'SMH ... I'm shocked'
• Text messager's 'Wow!'
• Online expression of disbelief
• Message board 'Holy shit!'
• Teen 'Whoa!'
• 2010 Usher hit featuring will.i.am
• 'Holy crap!', in a text
• Shorthand for the shocked
• Texter's expression of surprise
• "Ermagerd," in shorthand