Discussion boards are also known as forums, and generally present threaded discussion and comments in a collapseable tree view.

discussion boards are often integrated with a listserve and share the same characteristics, with the exception that discussionboards are far better at preserving knowledge - as you can search topics and postings for keywords. Preserving is not distilling though - forums are easy to set up but very inefficient in the long run as a way of collecting wisdom.

Users of support forums will almost always have to spend more time wading through responses, and will often have no indication as to which of multiple answers are correct.