It may be a bit of a stretch now to say that through his JustinGuitar website Justin has done as much for music as some of the other music-world "Sir"s have.
But he's young, far from done, and given time and the number of people he has taught (and will teach) to play across the globe, the benefits that being musical (rather than just listening to and buying music), and how those people touch the lives of those around them, in time I'd make a case that he will have done more in some respects than some of those "Sir"s
But maybe I am biased, being one he is teaching to play
