Related Clues:

• Guffaw in an AOL chat room
• "I'm hysterical!" in netspeak
• 'That's too funny,' to surfers
• "That's extremely funny!" in e-mails
• 'That's extremely funny!' in e-mails
• Texter's response to a hilarious joke
• Texter's guffaw
• 'That's hilarious,' in Internet-speak
• "That's hilarious," in Internet-speak
• It's somewhat stronger than LOL
• Texter's expression spelled out by the starts of 18-, 28-, 46- and 59-Across
• 'ZOMG! That's too friggin' hilarious'
• Texter's 'Hilarious!'
• Texter's 'That's hysterical!'
• Internet guffaw