Originally Posted by: da_ardvarkAnother way to make use of this is to understand and use MOST of the chord shape, but then eliminate fingers and use open strings. These "substitutions" can create an interesting feel. For instance try a C shape only use the A and D string. Move this around up and down the neck and I think You'll see what I mean. Also lets not forget about the other movable shapes. F, Am, Dm7 can also be shifted about.

Great topic!!!!
Substitutions, inversions and partial chord shapes can bring interest to a progression, as long as the manditory intervals are present.
An example would be a dominant 7th chord shape. Let's use E7 as an example. E7 = 1-3-5-b7 (E-G#-B-D) The manditory intervals that make this an E7 chord are; 1 (Root = E), 3 (Major 3rd = G#) and the b7 ( Dominant 7th = D). If any of these notes are not Present in the shape, it is not a E7 chord, so in reality the perfect 5th really could be left out and it wouldn't change the chord name. The 3rd makes it Major and the b7th makes it a dominant 7th. The reason this works is because the 3rd and b7 intervals from the root cause tension in the chord and makes it want to resolve to something to sound complete. What does it want to resolve to? A Major. Why? Let's look at the notes of the Major scale: = 1-2-3-4-5-6-7-------. The 7th tone of the Major scale is considered a Lead tone because it only needs to make a measily 1/2 step more to get home (the 8th tone = Octive = back to the root note. In the case of A Major that 7th tone would be a G#, the same tone as the 3rd of E7, so going from E7 to A Major resolves that tension, creating harmony and the dominant 7th tone of E is also the Perfect 4th of A. Notice that A is the perfect 4th of E.
Next post will show an E7 and A Major shape by just changing the fingering pattern some.