Nigel,
>...In the USA this cannot happen. The first amendment (freedom of speech) prevents an ISP from being responsible for anything posted on the site. This is what was reported, I don't know US constitution so, if I'm wrong, please be gentle :)
I don't know how the courts have interpreted liability related to ISP's for forum/bulletin board/web site speech issues. I can speak only from the standpoint of libel cases brought against newspapers, which are protected somewhat by "freedom of the press", a cousin of freedom of speech.
In order to prove a libel case, you must show that the *intent* of the newspaper was to harm the person or business involved. When there is "absence of malice" there is no case. That's why libel is difficult to prove, but not impossible.
Bottom line is, freedoms of speech and of the press carry you a long way, but do not give absolute protection.