A recent article in the Alberta Law Review by Matthew Nied discusses this further, Damage Awards in Internet Defamation Cases: Reassessing Assumptions About the Credibility of Online Speech. Nied is a recent UVic graduate, former Law is Cool contributor, and author of the Defamation Law Blog, which is currently on hiatus while he clerks at the B.C.S.C.
Nied proposes that given the hyperbole frequently found online readers are automatically more skeptical of content, and defamed individuals are therefore less likely to receive harm to reputation. The Supreme Court of Canada looked at the context of the statements to assess damages in Hill v. Church of Scientology of Toronto,
184 In considering and applying the factors pertaining to general damages in this case it will be remembered that the reports in the press were widely circulated and the television broadcast had a wide coverage. The setting and the persons involved gave the coverage an aura of credibility and significance that must have influenced all who saw and read the accounts. The insidious harm of the orchestrated libel was indeed spread widely throughout the community.
Nied suggests that online defamation cases, which can frequently be characterized by typos, grammatical errors, or in forums of questionable repute, should not necessarily be taken as seriously as defamation in other contexts. He cites Esson J in Vogel v. Canadian Broadcasting Corp.,  3 W.W.R. 97 at 178 (B.C.S.C.), discussing defamation in print,
[t]he identity of the accuser is an important factor. The accusation might have made by some nasty little tabloid scandal sheet and have done no harm. Strident scandal-mongering is the stock in trade of certain publications and, because it is, they have little or no effect upon the opinions of anyone whose good opinion matters. To their ugly accusations, it is a sufficient response to say: 'Regard the source.'
Richard Butler provides more background on Vogel at The Court.
The Ontario Court of Appeal has taken a different approach in Barrick Gold Corp. v. Lopehandia (2004), 71 O.R. (3d) 416, when assessing online statements, and increased the damages awarded at trial, which were limited given the rambling and often incoherent nature. R.A. Blair J.A. stated for the majority,
 The notion that Mr. Lopehandia’s Internet dialogue style – a style that may not be taken seriously in a traditional medium such as a newspaper – may undermine the credibility of his message has some appeal to those of us who are accustomed to the traditional media. However, as I have noted, the Internet is not a traditional medium of communication. Its nature and manner of presentation are evolving, and there is nothing in the record to indicate that people did not take Mr. Lopehandia’s postings seriously. In fact, the uncontradicted evidence is to the contrary.
The court also deal with anonymity, relying on the Alberta decision of Vaquero Energy Ltd. v. Weir to conclude that without being able to consider the bias of the author, readers would be more likely to take the statements seriously.
Despite Nied's canvass of English and American authorities and a rather compelling argument, I would still have to disagree with his conclusion in its entirety. Whereas a defamatory comment in print is in circulation for a day, a week or a month, depending on the frequency of publication, comments made online are permanent. For my purposes, a print story reproduced online is still primarily an online piece, because it will invariably be the primary source of retrieval post-publication.
I do agree with Nied that institutional sites are perceived as more credible, but I'm not convinced that credibility is the only window courts should look through. For example, there are the various factors listed by the Stanford Web Credibility review, or Karen G. Schneider's factors reproduced on Google Librarian. Should courts be assessing web design, looking for dead links, or counting the number of typos? Or should they be learning SEO and Google Page rankings, to determine the likelihood of readership based on how high defamatory statements rate for specific keywords, such as a person's name?
A 2009 study in the Journal of Retailing and Consumer Services divided users into an Internet-dependent group who primarily use the Internet for information, and those who still rely on other traditional media, what they refer to as a channel-dependent group. Although both groups used credibility to assess information, the Information-dependent group relied heavier on the perceived quality of websites. The channel-dependent group placed a higher emphasis on the compatibility between the information found online with their own personal values, but the Internet-dependent group put more emphasis on their confidence to evaluate the information online.
The point is that not all consumers of information online are the same. The Internet is still a medium that is evolving, six years after Barrick. Not everyone uses the Internet in the same way, and not everyone has the same skills when using it. Everyone will not react to defamatory comments online in the same manner.
Whether courts should continue to determine the perceived credibility of online defamatory comments, or if they are even able to do so given the current state, is an entirely different matter. Given the broader reach of online comments, I'm still okay with a rebuttal presumption of higher damages for online defamation.