Copyright has several key advantages:
Right to Produce/Reproduce - Copyright gives the creator of a piece of intellectual property (This includes Literary, Musical, Dramatic, or Artistic work; not ideas) the sole right to produce and reproduce their work.
Right to Authorize - These rights include the right to authorize others to produce or reproduce your work as well as the right broadcast your work.
Protection - Copyright prevents your work from being stolen or misused by others.
Moral Rights - Copyright allows the holder of the copyright to object to uses of their work that they find morally objectionable.
For a Limited Time only - Copyright only lasts for a limited time in Canada. It is different depending on the country of origin. But in Canada it generally lasts for 50 years after the death of the author, or in the case of cinematographic works 50 years after the date of "publication" or public release. This could be a good thing in that influential work will eventually pass into the public domain and be free for everyone to use.
These are several key disadvantages to Copyright holders:
Inability to Share Work - Copyrights key advantage is also it's primary disadvantage. Copyright does not allow you to openly permit others to use your work or to distribute it, even if they are not doing it for profit. This can mean that your work is disseminated slowly or not at all.
Authorship is not Ownership - You must own the copyright to be able to exercise the rights that it grants, and just being the creator of the work does not always guarantee ownership. In some cases the owner is actually the person who commissioned the work, or the company for whom the work was produced.
No Provision for Parody - Canadian copyright law does not allow for parodying of work without permission. Canada does not have a parody defense to infringement. Furthermore, Canadian copyright law does not make a distinction between using a work for commercial or non-commercial purposes. So a fan fiction author would not be successful in arguing that they wrote their Corner Gas derived story and did not make any money off of it. Any use of those characters would still be an infringement. Some copyright owners may not care if their copyrighted works are being sourced for fan fiction and others might, even if used for non-commercial purposes. (http://creativecommons.ca/index.php?p=scenario1)