Possible Clues:

• 'g2g!' response
• Brief sign-off
• Texter's 'Bye for now'
• Texter's "I'm out!"
• 'Chat another time!' in an I.M
• Brief "Chat soon"
• "gtg, see ya"
• "Ciao 4 now"
• "bfn" reply
• "g2g for now"