Capo, what is it? Lesson by rawood

A capo is a mechanical device that places a barre across the 
strings which as the effect of shortening the guitar's scale 
and thus raising its pitch. Huh? Basically we're talking about 
a clamp that puts a barre across the strings and makes the 
guitar's scale shorter. The effect is that you can play your
familiar open chords (i.e., the basic "C", "D", "G", etc.
chords you learned as a beginner) but now they're higher in 
pitch so you're playing in a different key. 
For example, putting a capo on the 2nd fret raises all open 
chords a whole tone. The result is that an open "G" now 
sounds like (and actually is) an "A" chord. A "D" becomes 
an "E." What this allows you to do is play in different keys 
and with different voicings using familiar chord shapes. 
Cool stuff....Cadd usually has a number behind it like Cadd9 
this is just snother chord shape....