i was lookin through the january 2006 issue of guitar world and saw a tab for the master of puppets riff. i've seen a lot of versions of this riff, but in this version, the very first chord of the riff looked like this:

(2)
2
0

is the note in parenthesis, one of those ghost notes? how do u tell the difference between ghost notes and tied notes in a tab? how do u play a ghost note? and what is it used for?