Yes and no. When you tap a string you generally pull it off. On a ghost note you don't pull off, and your not tapping it. You just lay your finger on a fret as you would if you were going to pluck the string, but you don't pluck the string. The loudness at which you play a ghost note depends on the music, the fact that makes it lighter is you don't pluck the string. Listen to a B.B. king solo, you'll hear tons of them. I think you got the idea, but just making sure.

Ex.

g--(9)-10--


The first note in parenthesis is the ghost note. To play this sequence just lay you index finger down on the 9th as your regularly would (not soft or hard, just normal), then when you go to play the 10th fret you pluck as as normal. You should hear the difference between the ghost note and the plucked one. The ghost note is fainter, no picking sound.