[korethr]

Poking around on this, this strikes me as a good, simple introduction to the basic concepts, without burying the newcommer under a ton of jargon, which has been been a recurring frustration of mine.

Some suggestions:

I might include a bit on the diatonic scale between the sections of the pentatonic scale and the chromatic scale. Anyone familiar with Western music should recognize quickly, as a great deal of well-known music has been composed using it. It should also serve as a nice half-way point between the pentatonic and chromatic scales -- introducing more notes from which to compose melodies but all of them still mostly sound nice with each other.

I suspect the reason you covered the diminished chord in addition to the major and minor ones is because that's the chord that works on the 7th interval of a scale, as you cover in the later section. But you might want to cover the augmented and suspended chords as well (perhaps in a later section). I'm probably not the only one who, when attemting to finger a chord on a piano or guitar, missed the 3rd or the 5th, and discovered another triad that sounds interesting.