Turn off your cell phones! This is not as big as a problem as earlier years but now with texting and apps it is making a hard come back. Having a cell phone ring during a movie has been one of the largest taboos when it comes to enjoy a film in a theater but now theaters remind you to put them on silent. But now with texting and game applications some people do not realize that the light emanating from a cell phone is also a distraction. In a dark theater the light can cast as a beacon of irritation to the people behind you.
Also if you must answer a phone call the best procedure would be to walk out of the theater in a calm fashion and then call your caller back. People who answer their phones in a movie are rude and impolite.
If you are a texter and waiting for an important text there are ways you can check without bothering people. Cover your cell phone with both of your hands and crouch down to read and send texts, make sure you use your body to block any light that may escape your hands. But obviously the best solution is pure abstinence of all cell phone usage, maybe even set up a voice mail greeting before the previews start saying you are in a movie and what time you will be out, and some cell phone have a texting auto-response system that can also let people know that you are in the movie.
For people who are annoyed by the frequent cell phone marauders the best thing you can do is politely let that movie criminal know that the light from their cell phone is distracting you from the movie.
The only exclusion from people not turning their phone off would be emergency technicians such as ER doctors, firemen, or police men and women who are on call. But even they should put their phone on vibrate to be considerate to others.