A synchronation is when a CD coincides or plays with a movie. The music of the CD "flows" well with the movie and often times the lyrics of the song pertain to what is going on in the movie.
I can't answer that. Most of these we're probably found by people on acid or something just experimenting with movies and music.
That also cannot be answered. Some of the syncs on this page would have been impossible to make because the movie was made after the album. These are just coincidents. Some, however, could have been intended. One, in particular, called "The Dark Side of Oz" has caused huge controversy. Others have had little impact. All are really fun (and trippy) to watch.
