Waiting for the HP, Z, whatever it's going to be called..
feels like waiting to find out who shot Mr. Burns --
feels like waiting to find out who Cartman's father was --
feels like waiting for Fry and Leela to actually get together --
feels like waiting for Mass Effect 3
feels like waiting for Half-Life 2 Episode 3
it's keeping people glued to the TV, the rags, the interwebz, etc..
Just like being made to watch 58 minutes of an hour news show, to see that big announcement during the last 2 minutes..