This is an amazing output level - not to mention they're apparently still taking college courses at the same time. To me; this only seems possible with incredible hearing capabilities - something achieved through ear training. You've probably heard of rock stars like Jimi Hendrix or maybe someone else like Beethoven being able to hear a song and immediately knowing how to play it without needing sheet music - that's ear training.
Ear training is something I have been lacking in my musical education - most music theory classes include ear training but my school doesn't. And that's where Teoria comes in! My guitar teacher showed me the wonderful music theory website that is Teoria a few years ago - before I'd taken any music theory - and it was all over my head then. But now that I've got the theoretics down, it's a great way to pick up things that I'm not strong at - like ear training. Truthfully I hope to be able to hear and write down music and songs as efficiently as marioverehrer, but that's a ways away.