To me, this term implies a person who is extraordinarily focused on something that average people would consider weird, overly complex, or merely boring.
Whether this something is airplanes, classical music, computers, chess, math, or something else doesn't matter too much. If you are a teenager, super-geekness can carry with it a stigma -- the very opposite of coolness. On the plus side, however, such extreme focus can lead to a very satisfying mastery of the subject of hand -- and the feeling that hey, this IS cool, even if THEY think it isn't.
Supergeeks value their individuality, though they may occasionally regret how hard it is to get a date! When they grow up, supergeeks often end up as engineers, scientists, or computer professionals -- figuring out the universe and designing and building all the stuff that defines the modern world. They are also some of the most interesting people on the planet!