Related Clues:

• 'Very funny,' briefly
• 'So funny!'
• Netizen's guffaw
• "Gr8 joke!"
• 'Ur hilarious!'
• OED initialism since 2011
• Typed guffaw
• "U slay me!"
• 'Haha, u r hilarious'
• 'That cracks me up!'
• "How hilarious!" in chat rooms
• Chuckle online
• "I'm cracking up," in a tweet
• Roaring online?
• Titter on Twitter