Crookes v Newton 2011 SCC 47 (CanLII) (19 October 2011)
From the headnote (emphasis added):
To prove the publication element of defamation, a plaintiff must establish that the defendant has, by any act, conveyed defamatory meaning to a single third party who has received it. Traditionally, the form the defendant’s act takes and the manner in which it assists in causing the defamatory content to reach the third party are irrelevant. Applying this traditional rule to hyperlinks, however, would have the effect of creating a presumption of liability for all hyperlinkers. This would seriously restrict the flow of information on the Internet and, as a result, freedom of expression.
Hyperlinks are, in essence, references, which are fundamentally different from other acts of “publication”. Hyperlinks and references both communicate that something exists, but do not, by themselves, communicate its content. They both require some act on the part of a third party before he or she gains access to the content. The fact that access to that content is far easier with hyperlinks than with footnotes does not change the reality that a hyperlink, by itself, is content neutral. Furthermore, inserting a hyperlink into a text gives the author no control over the content in the secondary article to which he or she has linked.
A hyperlink, by itself, should never be seen as “publication” of the content to which it refers. When a person follows a hyperlink to a secondary source that contains defamatory words, the actual creator or poster of the defamatory words in the secondary material is the person who is publishing the libel. Only when a hyperlinker presents content from the hyperlinked material in a way that actually repeats the defamatory content, should that content be considered to be “published” by the hyperlinker.
From the judgment of Abella J (who wrote for the majority, Binnie, LeBel, Charron, Rothstein and Cromwell JJ concurring; McLachlin CJ and Fish J concurring only in part; Deschamps J effectively dissenting) (emphasis added):
 … This Court has recognized that what is at stake in an action for defamation is not only an individual’s interest in protecting his or her reputation, but also the public’s interest in protecting freedom of expression …
 … Pre-Charter approaches to defamation law in Canada largely leaned towards protecting reputation. That began to change when the Court modified the “honest belief” element to the fair comment defence … and … developed a defence of responsible communication on matters of public interest. These cases recognize the importance of achieving a proper balance between protecting an individual’s reputation and the foundational role of freedom of expression in the development of democratic institutions and values …
 Interpreting the publication rule to exclude mere references not only accords with a more sophisticated appreciation of Charter values, but also with the dramatic transformation in the technology of communications …
 The Internet’s capacity to disseminate information has been described by this Court as “one of the great innovations of the information age” whose “use should be facilitated rather than discouraged” … Hyperlinks, in particular, are an indispensable part of its operation.
 The Internet cannot, in short, provide access to information without hyperlinks. Limiting their usefulness by subjecting them to the traditional publication rule would have the effect of seriously restricting the flow of information and, as a result, freedom of expression. The potential “chill” in how the Internet functions could be devastating, since primary article authors would unlikely want to risk liability for linking to another article over whose changeable content they have no control. Given the core significance of the role of hyperlinking to the Internet, we risk impairing its whole functioning. Strict application of the publication rule in these circumstances would be like trying to fit a square archaic peg into the hexagonal hole of modernity.