I used to call it "The Disney Info Site" and then "The D. I. S." (Disney Information Station). Now I call it "The DIZ". Have never called it "The DIS".
I always think "Diz" but figure it's just one of those things that either way is correct.
I figure if I ever see anyone I will just do a "Diz/Dis?" to them or something and make myself look like I'm clueless - it's not that much of a stretch for me.