The main purpose(s) of academic referencing can vary slightly depending on the genre, but typically include to:
- Give the original author(s) credit for their own work
- Validate arguments
- Allow the reader check the original work
- Demonstrate to the reader that you have read around the subject - particularly in essays.
- Avoid plagiarism.
- If an idea has become widely accepted to the point where audience familiarity is assumed, then it may be desirable not to reference it for sake of brevity.
- It may be unclear what to cite, especially does one cite the first use of a term or the best explanation of that term?
To add to the confusion, a lot of style guides insist on giving extremely detailed technical explanations on how to format references, rather than making the more important content-based decision to include or exclude a particular reference.