One important exception to the bar on use of copyrighted material is found in section 29.1 of Part III of the Copyright Act R.S.C. 1985, c. C-42, entitled “Infringement of Copyright and Moral Rights and Exceptions to Infringement”.
Fair dealing for the purpose of criticism or review does not infringe copyright if the following are mentioned:
(a) the source; and
(b) if given in the source, the name of the
(i) author, in the case of a work,
(ii) performer, in the case of a performer’s performance,
(iii) maker, in the case of a sound recording, or
(iv) broadcaster, in the case of a communication signal.
This provision ought to be used and explored in the context of discussion of music on the web.
Here is a portion of the ruling in Hagerv. ECW Press Ltd., a case before the Canadian Federal Court, Trial Division in 1998 on section 29.1.
I turn then to the meaning of “for the purpose of criticism” in section 29.1. I note first, that “criticism” is coupled with “review”. The principle of statutory interpretation noscitur a sociis would suggest that the two words are likely related. One relationship is that for the criticism or review to occur there need to be excerpts from and references to the works being criticized or reviewed. Also, when criticizing or reviewing any given work it may be necessary to use quotes from others for comparative purposes.
Among the definitions of the word “criticism” found in the Oxford English Dictionary , 2nd ed. (1989) are:
The art of estimating the qualities and character of literary or artistic work; the function or work of a critic. . . . spec. The critical science which deals with the text, character, composition, and origin of literary documents…
The jurisprudence has established that it is not merely the text or composition of a work that may be the object of criticism but also the ideas set out therein. Hubbard v Vosper,  1 All ER 1023 (C.A.) is most often cited as setting out the relevant tests.
Here is a web site from Heritage Canada’s web site in which the effect of Digital Rights Management (DRM) technology is discussed including on the exceptions to copyright protection, including the section 29.1 right of review:
Canadian copyright legislation also contains a fair dealing defence to claims of copyright infringement when a work is used for the purpose of private study, research, review, criticism, or news reporting and the manner of the use is fair. Other specific exceptions exist in the case of educational institutions, libraries, archives and museums, computer programs, incidental inclusions, ephemeral recordings, and sound recordings. It is true that Canadian courts have tended to apply exceptions to copyright infringement narrowly. Still — and this is the crucial point — the exercise of any exception presumes the ability to access a work. DRMs that prevent or severely limit access to a digital work render impossible an ability to exercise and enjoy the benefits of any exceptions allowed by law.