We try not to delete threads very often; we usually close them rather than delete them. Only when a thread is way off-topic and rancorous do we remove it.

While we have no way of automatically leaving a note about such removed threads, you're welcomed to PM any member of the community support team to inquire about a thread's removal. They will be happy to let you know the reason it was removed. If you are the thread's OP, you should already have received a notification from a moderator or administrator about why it was removed.

Best,
DocJohn