This is a question that Kevin O’Keefe answers in this post. He had received a question from a law firm where one of the attorneys was worried that by answering a blog comment, an attorney client relationship is formed.
Mr. O’Keefe responds by saying that its unlikely unless the comment is a specific question and the attorney gives a specific answer. The other issue that comes up if the attorney does answer specifically and the commenter is located in a different juridiction, there could be an issue of unauthorized practice of law.
Rule of Thumb
Mr. O’Keefe provides a couple ways for attorneys to look at this safely. Remember the reasonable man theory and also think of social networking as a different forum for familiar activities. So would it be reasonable for an attorney at a panel of industry professionals to refuse to answer question because there might be an issue that his/her answers could be construed as offering legal advice?