A forum is like an organism in that it is living. A sign of good health is when users respond to each other - responding is analagous to living or breathing.
When a fight breaks out, the fight becomes analagous to inflammation where the body(forum) is trying to heal itself. The forum is trying to rid itself of infection.
Like an organism a forum can become scarred. The scar usually presents itself sometime after a wound has healed in the form of forum culture.