What I have always wondered about, if someone posts libellous comments about someone one else on a site. Where does jurisdiction lie?

Is it in the country that the server that the site in question resides on, or is the country where the site conducts its business.

For example the site is hosted on a server in the netherlands, however the company behind the site conducts its business in the United Kingdom.

Which country's laws could a site be prosecuted under?

That's going to be one for the lawyers to resolve for you.

Depending what is being stated on the site, if you have a decent raport with the site, you may be able to have the comments removed. If things are flat out lies, you have a better chance, but you need to prove them.

One of the beauties of the web forums is that there is a lot of room for people to make comments and post experiences, but just like a newspaper there can be legal suits brought against the poster for invalid content.

Where the legalities are however, that's something that a lawyer would have to determine - If the issue is with a particular company, I'd THINK that you would file the suit against the company, rather than the location of the data - but again, legal advise is recommended on this, I am not a lawyer.

Libel on the internet as a international problem as I've coincidently passed a site that talks about the abuse of the Internet and has forced lawmakers around the world to try to maintain some degree of control over what is placed upon the Internet. Individuals posting by defamatory statements have frequently looked toward libel law for remedies. However, since communicating via the Internet occurs in a unique manner, there is great uncertainty as to how traditional libel laws should be applied.