The other participent says "bye"--or something-- The original person says "bye"/whatever again, and the other one responds. This can go on for minutes or longer until someone--or their parent--puts their foot down.
SampleSNperson8: call you later
SampleSNperson8: yea, cya
ExampleScreenName1: OK I HAVE TO GO NOW!!! PARENTS!!! GAH! BYE!
SampleSNperson8: OK!!! BYE!!!
"Aren't you worried about the Republicans? Once they get into office, they'll reduce the size of government." "If only!"