Montage

The Russian Revolution in 1917 introduced the montage to give images new meaning.
A cut can completely change depending on the other shots that surround it.
"Why oppose only when there's a war?
Why defend the clinics only when they're attacked?
Why are we always reactive?
Whatever happened to protesting nothing in particular, just protesting because it's Saturday and there's nothing better to do."
- King Missile
That's a completely irrelevant King Missile quote just because we're talking about revolution and watching Battleship Potemkin and stuff. You can ignore that one I guess.

Dziga Vertov has the real Kino Eye
Tried to create cinema that imitated real life and was more than just a movie.
Man with a movie camera is the greatest documentary ever made, I've gotta watch this one for real.

Vsevolod Pudovkin said that actors on screen don't act, it's their context that moves us.
Editing is completely unique from all other art forms, or at least it was back in the day.
You can imply things or suggest things using just editing.

Contrast - Force viewer to oppose two or more shots in their mind. 
Parallelism - Using similar shots or themes to show difference in time.
Symbolism - It's symbolism.
Simultaneity - Stuff going on at the same time, can be used to mislead.
Leit Motiff - Usually a musical theme - A recurring shot that means something.