With all that goes with Nerdfighteria, by all accounts, this is the only acceptable definition:
Made of awesome
"where normal people are made of tissues and bones and organs and stuff, nerdfighters are made of awesome"--John Green on Brotherhood 2.0
Youtube celebrities John and Hank Green who spent the year 2007 refusing to communicate through text. Everyday they communicated through vlogs on Youtube, alternating days. They amassed several thousand subscribers.
They extol the virtues of the nerd life, calling themselves and their fanbase nerdfighters and those who aren't nerds decepticons.
They acheived some fame when Hank's song "Accio Deathly Hallows" was featured and expressed the sentiments of nerdfighters everywhere.
Wow, did you check out the "in your pants" forum on brotherhood 2.0 yet today?