What do the blue dots mean?

The blue dots signify the fifth note or degree in the scale. This is a very important note in the guitar scale and Western music in general. It is the dominant note in the scale and amplifies the intensity of a song or melody. It also hints or suggests to the listener that from this point the melody will go back to the octave and resolve. The seventh note in the scale is even more profound as a note to resolve back to the octave from.

But if you can remember the note positions of the fifth degree and the root note in the scale, identified by the blue and red dots respectively you will have two excellent visual markers in the scale to keep you oriented.