The guy who feels the need to be a "troll" online. Found on Forums and social networks like FB or MYB. A clear indication they are being That Internet Guy, is when he posts on a girls' status that is 7 or 8 years younger then him, and make idle threats to seem bigger and have balls.
Did you see that guys' post on that 18 year old girl's status?
Yeah, he is totally being That Internet Guy.