Copyright is one of the most powerful tools a business or individual can use to protect their creations and intellectual property. When material is copyrighted, those who don't have the copyright holder's permission can't replicate it for use. A copyright isn't difficult to acquire. However, not everything can be copyrighted. There are some types of materials that are actually specifically excluded from copyright law.
Generally, a work needs to be in a tangible form to be documented. For example, a piece of choreography would need to be diagrammed or documented in some way to be copyright eligible. If the choreography only exists when it is performed, then it can't be copyrighted. Also, ambiguous assets like thoughts, ideas, concepts and processes cannot be copyrighted. For those types of materials to be copyrighted, they would have to be documented in the form of a written description or illustration.