Fair Use is copying a little amount of copyrighted work for such as parodies and mashup videos, but it is limited. You don't need to get permission to use so some parts of the video.
Piracy is illegally copying someone's copyrighted work without their permission or paying for it.
Plagiarism is using someone's words, idea, or things without giving credit to the person who is the creator of the words, idea, or thing.
Digital Footprint is a track of photos, videos, comments, and anything you post online, what you post today will stay online the rest of your life.