Regarding shape note music (which is also called Sacred Harp, after one of the more popular books of songs): The tunes are notated on a standard staff with time signatures, bar lines, half/quarter/eighth notes, etc. Each note head, however, is given one of four shapes, representing the syllables fa, sol, la, and mi. The major scale, instead of do, re, mi, etc. is fa, sol, la, fa, sol, la, mi, fa. I've heard that this is an older method of solfeggio than do-re-mi, but perhaps not. Obviously, this system is not well suited for notation independent of the musical staff. I believe the reason it was popular is that it gives a visual reinforcement of the intervals between different pitches, thus making sight singing and tune learning a little easier. The tradition (well, one tradition, anyway) in American shape-note singing is to sing the tune through with shape names, followed by the words as written. This makes for some challenging eye-tongue coordination!

Sometime Mudcatter Chocolate Pi is active in the shape note community in the Chicago area, and I used to be a member of the Sacred Cow Harmogenizers in Seattle. It's great fun!