-8the estimation of right-thinking members of society generally 10 ) about the person defamed. It follows that the act of publication is a fundamental constituent of the tort. 17. In seeking to decide whether and to what extent the respondents should in law be treated as publishers of the defamatory statements posted on the forum, it is necessary to examine the established common law rules on what constitutes “publication” of a libel. 18. As Isaacs J explained, “To publish a libel is to convey by some means to the mind of another the defamatory sense embodied in the vehicle ...”11 It is a bilateral act, as was pointed out in Dow Jones & Co Inc v Gutnick: “Harm to reputation is done when a defamatory publication is comprehended by the reader, the listener, or the observer. Until then, no harm is done by it. This being so it would be wrong to treat publication as if it were a unilateral act on the part of the publisher alone. It is not. It is a bilateral act – in which the publisher makes it available and a third party has it available for his or her comprehension.”12 19. Until mitigated by the common law defence of innocent dissemination which evolved in the late nineteenth century, liability for publishing a libel was strict and could lead to harsh results. A person was held liable for publishing a libel if by an act of any description, he could be said to have intentionally assisted in the process of conveying the words bearing the defamatory meaning to a third party, regardless of whether he knew that the 10 Gatley on Libel and Slander (Sweet & Maxwell, 11th Ed), §§1.7-1.8, citing Lord Atkin in Sim v Stretch (1936) 52 TLR 669 (HL) at 671. For other formulations of the meaning of “defamatory” see Duncan and Neill on Defamation (Lexis Nexis, 3rd Ed), §§4.01-4.02. 11 Webb v Bloch (1928) 41 CLR 331 at 363. See also Gatley, §6.1 and §6.14. 12 (2002) 210 CLR 575 at §26, per Gleeson CJ, McHugh, Gummow and Hayne JJ.