I had 8399 posts yesterday. Today I have written four posts and my current post counter is at 8400 posts. Can it be that (old) posts are deleted without being informed?
The posts which are copied or posts/thread which is already available on the forum can be deleted by mods without notification.
It is not always a moderator, people sometimes delete their own threads and since the thread isn't yours, and it wasn't deleted by a moderator, you get no notifications for it.
Only mods can delete threads.
We can only delete posts.
We can delete posts only after 24 hours. And in few sections of forum, we are not allowed to delete our posts or thread (for example Auction).