From time to time certain posts are made on forums / bulletin boards that are in conflict with the focus or view of the board owner or community. At these times the thread maybe closed (ie no more posts accepted) or deleted.
The said thread can then become a rallying point, or Martyr for disruptive community / individual behavior.
Someone brings up a controversial issue / matter which subsequently causes arguments and unacceptable forum behavior. The post is then closed, after which persons begin opening new threads that refer to the closed issue in rebellion to the authority that administrates the board. Community members may also form factions which can then cause further community instability.
The thread could then be called a Martyr Thread.