Possible Clues:

• "Whoa!" text
• 'Wow!'
• Texter's gasp
• Texter's "Crikey!"
• Texter's 'Yowza!'
• Three-letter 'Squee!'
• 'That's so weird!' online
• Texter's 'Crikey!'
• '!!!!,' in a text
• "Heavens!" to a texter