What's a nub?!
Simply put, a nub is the 100th part of a boon. You get these smaller units by getting your tracks played back, by your grafix being seen and downloaded by users, etc. Accumulating nubs gets you boons, and it's easier to gain nubs since they're smaller 'units.' For more information, see Boons.
Not to be confused with a n00b.
XD