i think a sig is something that shows your originality as well as expressing you my sig is a manip of a macro shot i took of my eye
Nope. If say you use a few techniques (emphasis on a few, like one or two steps) for a completely different work to the tutorial, I see no problem. But following it to a tee might as well be copying.
I think a sig expresses one's artistic creation and imagination. Also expresses a certain personality.