We have every right to critique our local fish shops in the same sense the media has every right to critique a new film, actor, show, book etc. As long as everything is truthful and factual it is impossible for the powers that be to come down on the forum screaming "libel". If it were, the media industry would be completely screwed. I remember Microsoft trying to have various discussions removed from forums years ago where people were saying there operating systems were rubbish but they didnt get anywhere with it. Its completely impossible to police which is why 99.9% of cases never get further than a snotty letter.
PS, Slander is for the spoken word.
Anyway, not quite sure i want to get into a debate about it, i had all this years ago setting up a forum for a UK newspaper and it was a nightmare, every legal team wanted to bury their heads in the sand