A fan is a person enjoys this special person's gifts.
Whether they enjoy their books, they life or even guitar riffs.
A fan is a person who buys one's CD, Movie or book.
One who has respect for the person. Respect meaning, no flaming, or stalking. I myself am interested in one's and favourite song\movie. But its too far when you want to know where they are all the time, and you think you really know them in reality, but you really don't.
Example, my friend thinks she knows Eminem in person, but she never met the man, and she's always saying how she was talking to him and he says this and that.
pretty scary
I believe this is what you call a fanATIC