Apparently it means Super
Über or ueber (DE_uber.ogg German pronunciation (help·info)) comes from the German language. It is a cognate of both Latin super and Greek ὑπέρ (hyper), as well as English over.
Ampersand - Wikipedia, the free encyclopedia
In alot of video games and teen chat rooms, people use Uber alot, so i guess it finally made its way to these forums