What is thread derailment?
Thread Derailment occurs when a thread is steered away from the topic discussed in the original post to a different topic completely.
What is going to happen?
Simple. We are going to issue official warnings. Then we will issue suspensions. Then we will issue the final 1000 year ban.
What prompted this?
Bad behavior. Thread derailment has always been against the rules but enforcement has been relaxed. No more. If the topic intentionally gets derailed then expect the process described above to be followed.