When someone is seriously "bringing the lulz" and making people laugh either on purpose, or by being laughed at.
"I was laughing so hard! You should have been there. That guy was selling rofl tickets."
The art of brushing up one ones unorthodox online gaming skills.
"Oh man I've been offline for at least 12 and a half minutes, I've lost my edge. I'd better do some haxorcise."