The imaginary line marking the difference between Applied Phlebotinum which is a cool and interesting adjunct to the story being told, and Applied Phlebotinum which is the story being told. Story quality plummets dramatically the further past the Roddenberry Line you get. What side of the Roddenberry Line you're on can often be determined by the amount of Techno Babble you have to wade through before you can find a real plot point or a believable character.