kind of an ITUNES noob question

[Sgtarky]

I have fought all these years to not use ITunes now I am getting around to using it. when you bring something into ITUNES is it make an extra copy or is it simply a link? I noticed when I pulled a movie into then deleted the movie from the folder it was in, it still showed up in Itunes....I would much rather it be links instead of having 2 copies of files. unless I am not understanding the function.