1. The single most effective way of preventing such tragedies in the future, or reducing their likelihood, is for President Obama and Congress to step up and restore the ban on assault (semi-automatic) weapons. No law-abiding citizen should have need for them. Their banning would not violate the Second Amendment - which, unlike the First Amendment, does not say "Congress shall make no law". Rather, the Second Amendment says government should not "infringe" upon the rights of people to bear arms. The banning of a weapon of mass killing would not infringe on the right of citizens to bear other kinds of guns. (Just a ban on sale of assault weapons to anyone under 30 years of age would help - it would have prevented the attack on Rep. Giffords last year, the murders at Virginia Tech, and what happened in Aurora.)
2. The notion that violence in the movies or in any medium triggers this kind of real-life violence is not supported by the facts: Millions and millions of people have watched violent movies and television, and played violent video games - and, thank goodness, mass killings have happened just handfuls of times. (See my debate with Jack Thompson a few years ago about violent video games for more.)
3. But motion picture theaters need to think of ways to make their premises more safe. Movies - especially horror movies - have for decades sought to give the viewer tingles of fear by showing people on the screen menaced and killed by monsters and psyschos in the darkness. With what happened in Aurora, Colorado making this a reality, the motion picture industry may need to rethink such movies, or at very least provide increased means of protection in theaters, such as metal detectors. Motion picture theaters have in effect been on the ropes since the rise of television in the 1950s. The ease today of also viewing movies on tablets and smart phones is only putting more pressure on theaters. Unlike schools, where attendance is required, movie-going is strictly optional. The public needs to feel that exercising this option is safe.
4. The Batman franchise - in particular, The Dark Knight trilogy - will likely forever be associated with the tragedy of Aurora. The Batman story, at its core, is about the darkness in the human soul (which Batman is able to overcome, or channel into doing good). The spilling over of this darkness from fiction into our reality - where it of course already exists - is a signal moment in the history of movies, and even story-telling in general. What impact this will have on Batman's place in our popular culture is hard to say - it will likely make the masked crusader both more and less intriguing - but we can be sure that Batman will never be seen the same.