Deleted Outbox Message

If I delete a private message in the outbox does that remove my copy of what I sent, or mean that the party it was sent to will never receive it?

if you delete private message from outbox will not perform deletion of of sent item sent. so you need not to worry about it.

I think it means the person you're writing to will not get the message.

If you delete a Private Message while it's still in your Outbox, the recipient will NOT receive it. However, if they have elected to be notified by Email when they receive Private Messages, they'll know they had one, but that it was deleted before they could pick it up. I believe they will also know who sent the PM to them AND that it was deleted.

Correct, that's the way it seems to work.