To type incoherently while blinded by rage and threaten strangers on the internet for imaginary slights.
Characteristics are swearing, threatening the stranger with death, arrest, and lawsuit (in that order), sending the stranger emails/IMs every three minutes, repeating phrases you heard in action movies, and finally, threatening to get their account banned because they were picking on you.
Basement dwelling is optional.
I tell the new poster that his anime drawings needed work, and he starts whining Pacione-style. He sent 20 private messages calling me a 'hell-bound whore' and threatening to tell my employer that I am picking on the disabled in one hour.