A perennial problem with defamation on the internet has been that of tone. Casual conversations - on bulletin boards or blog post comments - can feel as though they are transient and ephemeral. People write in a way which they would never use in a more formal setting such as a newspaper's letters page. But this perceived informality may clash with the approach taken by libel lawyers and courts, who are used to parsing newspaper articles closely for any possible defamatory meaning and who may apply this approach to turn the loose language of a post into something defamatory.
Offline, casual conversations also benefit from the more relaxed rules of slander, where oral (as opposed to written) communications generally don't give a person a right to sue for defamation unless they have suffered actual damage as a result. Online, though, the distinction between slander and libel evaporates so that (in most jurisdictions) an internet posting - however casual - will be treated as libel rather than slander, giving a person a right to sue irrespective of whether they have suffered any actual harm.
Significantly, however, in Smith v. ADVFN Mr Justice Eady took the informal nature of bulletin boards into account in deciding whether a claimant had a chance of succeeding in a defamation action, holding that these cases should often be treated as closer to slander so that the casual nature of posts should be taken into account when interpreting them. His summary of "the nature of bulletin boards" is worth quoting in full:
13. It is necessary to have well in mind the nature of bulletin board communications, which are a relatively recent development. This is central to a proper consideration of all the matters now before the court.More on this case - including the way in which the claimant attempted to use defamation actions to silence his critics - at The Register.
14. This has been explained in the material before me and is, in any event, nowadays a matter of general knowledge. Particular characteristics which I should have in mind are that they are read by relatively few people, most of whom will share an interest in the subject-matter; they are rather like contributions to a casual conversation (the analogy sometimes being drawn with people chatting in a bar) which people simply note before moving on; they are often uninhibited, casual and ill thought out; those who participate know this and expect a certain amount of repartee or “give and take”.
15. The participants in these exchanges were mostly using pseudonyms (or “avatars”), so that their identities will often not be known to others. This is no doubt a disinhibiting factor affecting what people are prepared to say in this special environment.
16. When considered in the context of defamation law, therefore, communications of this kind are much more akin to slanders (this cause of action being nowadays relatively rare) than to the usual, more permanent kind of communications found in libel actions. People do not often take a “thread” and go through it as a whole like a newspaper article. They tend to read the remarks, make their own contributions if they feel inclined, and think no more about it.
17. It is this analogy with slander which led me in my ruling of 12 May to refer to “mere vulgar abuse”, which used to be discussed quite often in the heyday of slander actions. It is not so much a defence that is unique to slander as an aspect of interpreting the meaning of words. From the context of casual conversations, one can often tell that a remark is not to be taken literally or seriously and is rather to be construed merely as abuse. That is less common in the case of more permanent written communication, although it is by no means unknown. But in the case of a bulletin board thread it is often obvious to casual observers that people are just saying the first thing that comes into their heads and reacting in the heat of the moment. The remarks are often not intended, or to be taken, as serious.