Therefore usually messages of the last few days are up. Messages earlier than that have been permanently purged. If the message is recent then it is likely your post was deleted by a forum cop. Occasionally, because it is easy to do, a cop can delete a message that he was not intending to delete. Or he may delete a whole thread of messages because of the nasty tone of many and it is possible that innocent posts within the thread were deleted as well.
Acronyms save time and often replace facial expressions to help give a post the appropriate tone.