Someone who brakes his or her car for no apparent reason. This person could be driving in front of you, or, God help you, may be the driver of the car in which you are currently driving.
TOM: (yelling out the window of his car) Hey! What are you braking for? There's nothing in front of you! Come on! Move it!
SAM: Tom, he's just a random braker, dude. His first instinct is to brake. They suck...
A sarcastic statement mocking the type of netspeak that is popular among 12-17 year olds. When spoken in word, it is spoken in a serious (thus ironic) voice while pronouncing the "xd" as "ex dee".
You're wearing a Hot Topic Invader Zimshirt, huh? Well would you look at that, he's riding a moose and Gir is eating a taco. Lol so random xd.