Terminator: Salvation is a great sci-fi action movie. I'm not sure it's a great Terminator movie but that's not relevant right now. One of the things that has become part of many continuing movie series is great bits of dialogue that show up again and again. Like in T4, John Connor has the "I'll be back" line. Star Wars of course has "May the Force be with you" but it also has "I have a bad feeling about this." In the same way, Star Trek has "Are you out of your Vulcan mind?" These lines are ways to connect the movies in the minds of people who've seen the others.
I'm thinking now of how to do that in the stories I'm writing. Maybe put in some bit that keeps happening or some other continuing inside information. Of course, with my stories the line most likely to be used is "Hulk smash!"