Summarize this article in one sentence.
This is a very important feature when you want to fuse one note into another (Syn always does this). If you have a whammy bar, just push it in and the note will get higher. If you don't, just play the note and force the string up or down the way to make the note a higher note, 1-3 frets higher. This is very important. Usually Synyster has the sound distorted but not always. Syn plays fast, but he plays clean. Syn uses this quite a bit and is heard and almost every song. This gives it that type of open sound Syn trademarked.

Summary:
Learn how to sweep pick. Learn how to "bend the strings". Learn all the scales forwards and backwards. Make sure you don't rush through your licks. Learn how to do dive bombs effectively. Learn how to use harmonic dive bombs. Follow the chords with arpeggio sweeps and string skips.