There's a special helmet that we receive upon initiation* that lets us enter the internet with physical embodiment (think TRON, but less spandex). Using this, we do hand to hand combat with all manner of vile Troll and Spammer. Many mods have died in the line of duty, but we try not to think about it too much (as death is generally accompanied by rejection of your brain by the helmet, followed by a brainsplosion, which is pretty messy). I would talk more, but the Limo Smeagol bought for me is waiting; I'm about to go to a Mod party and pick up some chicks.
*Initiation is a long, grueling process in which we have to walk in circles for the equivalent of 300 miles, barefoot, naked, in the snow. Our only nourishment is a small crumb of bread dropped in the center of the circle weekly. To get the bread you have to fight off a half starved bear with rabies. Other than that it's pretty easy to get in.
I hope this has been enlightening.