The newsgroups are great for learning, help and advice and many businesses are benefiting from it by posting questions.
Marketing can be an expensive business and is a game of risk reduction.
I have seen posts where the advice is just plain wrong though it looks credible. The newsgroups are discussion groups and as in real discussion points are just let go. It is just not worth arguing with people who have made up their mind and it is boring. Unfortunately, this attitude is downright dangerous to business people taking part. Remember, moderators do not look at content, so business is unprotected.