#1
What is this. I have been told that it is a good tool to know, but what is it? When i google it, I keep finding places to "purchase the secret". (ugh...) could someone explain it to me?
#3
http://en.wikipedia.org/wiki/Nashville_Number_System

The Nashville Number System is an informal method of transcribing music by denoting the scale degree on which a chord is built. By writing chords as numbers, music may be transposed easily. As a simple system of transcription, it can be used with only a rudimentary background in music theory, and may not be as intimidating to learn for musicians unfamiliar with traditional notations. If a set of musicians has basic familiarity, improvisation and jam sessions can be quickly explained using numbers, and chord changes can be communicated mid-song by holding up the corresponding number of fingers. The system is flexible, and can be embellished to include more information (such as chord color or to denote a bass note in an inverted chord) as the user desires.