I think Bingo (cool name-o) is referring to a similar question I posted a while back. There are several examples of chord progressions which are directly derived from the Major scale. The classic example is the II - V - I progression. Using the Cmajor Scale as an example, all of the notes in the II(Dm7), V(G7), and I(CMaj7) chords are directly derived from the C Major scale. There is no need to alter notes from the scale to create the chords. Theoretically, you could play all of the notes from the C Major scale over that progression, even in random nonsensical order, and it wouldn't sound tonally incorrect.

One would think that the I - IV - V Blues progression, because it is so commonly used and versatile, would have a similar derivation -- That the chords for the I - IV - V Blues Progression could also be derived from one common Major Scale without having to alter any tones, but it just doesn't seem to be the case. The I and IV chords have to be altered and at least one note from the Major scale fails to work well over that entire progression. I realize that the Major and Minor Pentatonic scales will always work over the (I7 - IV7 - V7) progression in the same way that the Major scale works over the II - V- I, but I don't believe that the I - IV - V progression was actually derived from those scales. For whatever reason, this commonly used progression seems to go against the rules that work for many other common progressions.