In Silberberg v The Builders Collective
of Australia Inc [2007] FCA 1512 the Federal Court of Australia held that the person who posted messages on to an unmoderated Internet discussion forum which contained material which caused
offence and distress to the subject of the messages because of his Jewish race and ethnicity breached Pt II of
the Racial Discrimination Act 1975 (Cth). But the forum operator was not held liable.

Whilst the failure of the operator to remove the material was offensive, the trial judge could not conclude that the operator’s failure to remove the offensive material was
attributable, even in part, to the race or ethnic origin of the applicant.

He distinguished the test under the Racial Discrimination Act from the liability of a publisher for defamation or breach of copyright. 

Is the Collective
responsible without actual knowledge of the offensive contents of the messages?
If the question arose in defamation or breach of copyright, the answer is likely
to be in the affirmative. The Collective chose to conduct an open anonymous
forum available to the world without any system for scrutinising what was
posted.  The party controlling a website of such a nature is in no different
position to publishers of other media. In my opinion, failure to remove the
offensive material within a reasonable time of it having been posted was an act
caught by s 18C(1)(a)…

However, there is substance to the argument that the failure to remove
the offensive material has not been shown to have any relevant connection with
race or ethnic origin of the applicant or indeed any other Jewish person as
required by s 18C(1)(b) of the Act. The failure of the unidentified
administrator to remove the Second Message on and after 1 July 2006 was the
clearest case of failure to act.  I cannot conclude that such failure was
attributable, even in part, to the race or ethnic origin of the applicant.

For further comment on this case see this post by a representative for the forum operator. See also his comments on other cases pending relating to forum operators.