An expression of when someone displays that they are undoubtedly a noob or when an experienced gamer does something ridiculously stupid to make you laugh and call them a noob anyways.
Most likely used by some corpies playing Eve Online. Typically relates to ridiculous fits on ships but the term stems from people mining in asteroid belts and getting helplessly ganked, lulz.
"Bahahahaha, you just fitted four different types of weapons, a shield booster and armor repairer on your ship. Noobranium"
"Dude! I just lost command ship!" "Why?" "...I fell asleep on the gate..." "lulz, Noobranium!"
"Hey, I hear theres tons of noobranium on the ice belt right now" *Smartbombing battleship dives in to the rescue*