To vent your frustration; either loudly or through the Internet. Most people prefer the Internet, like going to VentNation.com or related sites, or going bat s--t crazy and ranting in someone's face. Sports fans and TV personalities enjoy ranting the most, and so do girls amongst their friends.
Person 1: Why are you ranting?
Person 2: Because I'm unemployed. I don't have a girl. I hate my life! FML!
Person 1: I HATE THE PATRIOTS. TOM BRADY IS A NO GOOD PRETTY BOY AND BELICHICK IS A BELICHEAT.
Person 2: Stop ranting and calm down!