Users can delete their own posts. If the deleted post is the first in a thread, the whole thread is deleted.
Recently I was accused of deleting a post that disagreed with me. I would never do this. People disagree with me all the time, lol. We have strict rules in place for what moderators can and can't do. If a post is blatantly in violation of the posted rules, we can pull it on the spot. If it's questionable, we have to discuss it and reach a consensus.
Also threads may be moved to more appropriate forums, or rarely, a thread can be split if multiple distinct discussions that merit their own threads develop within a single thread, and we happen to catch it.
So if you think a post or thread has been wrongly deleted or you see something strange and it bothers you, please don't hesitate to email and ask us.
Thanks.