“Other certain speech is probably also a bad idea (e.g. investment advice, tax advice, etc.) in such a forum.”
Wouldn’t you just love to be a juror if someone sued for bad investment advice on a blog from a random person. I would constantly send notes to the judge from the dilberation room in hopes they would be read in court, something like this “the jury has requested 12 large bats with the words “dummy stick” written on them so they may beat the plaintiff senseless.”
Purporting to be an expert and stating one’s credentials, then giving advice known to the author to be untrue, harmful or misleading is one thing. But us yahoos giving our opinions is a risk I’m willing to take and something that our constitution and laws are designed to protect. Many a man and woman have given their lives to protect this freedom, it’s our responsibility to exercise it.