An interesting case concerning defamation on the Internet: see the Supreme Court of Canada decision, Crookes v Newton, 2011 SCC 47.
The defendant operated a website offering commentary on various issues. An comment included hyperlinks to two other pages, both of which contained articles that the defendant conceded were defamatory.
One hyperlink was "shallow," in that it referred to a web page on which the defamatory article was one of several articles posted there.
Another was "deep," in that clicking on the link led a viewer directly to the article.
For different reasons, all judges decided that this hyperlinking was not a "publication" for Canadian defamation law.