What is a fanlisting? It's really nifty! A fanlisting is a list that anyone can submit their names to so they can show their love for a certain thing; in this case, Anathema is a fanlisting for Black Jack. And as a neat, little bonus, you get to take a code, or button, and put it on your site to show off your adoration for sensei.
So... What are you waiting for? Go ahead and join!