One who runs a forum or is an active member of one or more forums.

Best described as a torrent of little children running around in a minefield (users), some armed with weapons (moderators), forums are the flagship of internet discussion, spam, and flame wars.
Smaller forums tend to be more habitable, but the larger ones have many distinct and similar features. For example, within approximately seven seconds of the creation of a topic, you will have at least one reply, garunteed. Large forums also tend to spawn makeshift caste systems within themselves, and you're automatically a malefactor in the forum until you have a 4-digit post count.
A forum can sometimes be helpful, but normally they become a time consuming and frustrating thing if you pay too much attention to them.

A place on the internet within a site in which people can discuss topics with other people. A Forum is separted by topic sections and those are divided by sections called "threads" (You are the one who creates the thread, and see how many people respond to you, or view your opinion). Forums are operated by moderators. Forum moderators are usually offended by the smallest imperfections (they are usually power freaks). In many Forums, you are not allowed to swear or insult people, displaying pictures of naked people or gory/bloody incidents.

An internet-based Bulletin Board in which members can post thoughts and views. Based on the Roman word 'forum'.
Forums have a general hierachy:
Administrators
Global Moderators
Local Moderators
Premium or Paying Members
Members
Validating Members
Guests
Banned Members
They are alsp a popular target of hackers and crackers and a paradise for spammers etc.

(Computer Science) to spend copious quantities of time religiously reading and replying to posts on online bulletin boards (forums).

A series of waste dumps on the Internet to put all those ideas any decent human being would keep to themselves.

Verb

When two or more people participate in sexually scandalous conversations via online forums, particularly in forums relating to MMORPGs such as World of Warcraft.

Can also use forumication, forumicating.

The word "forum" is derived from the Latin word "Fora". A large public meeting place. Similar in origin and function to other words used today when describing public speaking. "Community" and "Committee" originate from the Latin terms "Comitium" and "Comeo" and today's podium is referred to as a "Rostrum" from the original stone tribunal called the "Rostra". The people of ancient Rome would meet in the "Comitium" to listen to orators speak from the "Rostra". When the city grew larger the Roman Forum" was built to accommodate larger crowds.

Gaius Gracchus, a tibune of Rome is famous for turning his back on the Senate in the "Comitium" while speaking from the "Rostra" to face the common people gathered in the forum on the other side. From that point all orators spoke with their back to the Senate House.

Today the term "Forum" is defined as an online Internet message board section or "forum" where people leave posts with their opinion and comments. Each "forum" is separated into specific interests like, politics, news, pics etc.

It's usually used with a forum host, with a ridiculously long URL. Forums are used to post messages, but these days are used for support rather than entertainment. Moderators and Administrators usually moderate the forum and even use their ban hammers if necessary.