Here is a short definition of what a web forum is, for those of that are not familiar with them.
What is a Forum?
A forum is public meeting place for open discussion of various topics. Online, a forum may also be referred to as a bulletin board or discussion area.
Forums come in all shapes and sizes. The main objective is to provide an area where users can interact with questions, answers and discussions on a given topic.
There are literally thousands and thousands of topical forums online. Each forum usually states the topic and tries to keep the discussions on topic. However, this can often vary from forum to forum.
How do I Use a Forum?
Forum use will vary from forum to forum. In general you are required to create an online identity [ID or nickname] to be used on the forum. While some forums are free, others have a paid membership requirement. Be sure to read privacy policy before creating any identity online. Parental permission is usually required for reputable forums.
Some forums allow "Guest" access so you can view the forum before joining. This is a good way to check out a forum before you decide if you want to join. Look for a "Guest" option before signing up. You will not be able to actively participate in most forums as a guest.
If you decide to join a forum and have your forum ID you will be able to log in the forum, read what has previously been posted, start your own discussions or reply to discussions already started.