If I delete a message I sent to another Facebook user, will it also be deleted from that other user's message inbox?
The Facebook messaging system, as far as I can tell, doesn't have a "draft" and a "trash" section, and doesn't use the term "email". The Facebook messaging system is akin to IM chat.
I understand that email works differently than Facebook's messaging system but don't know if deleting from my end will also delete from the recipient's inbox.
No. Each message is transacted with a unique email ID. The inbox for each user is independent of messages. i.e., the message you send is not linked and stored internally with the inbox of the receiver.
Each mail transaction like draft, inbox and trash act independently with regards to the email user. Hence, manipulating any message will only reflect your email.
At least no major service provides allow such cross deletion.
Any messaging system doesn't allow you to delete item from another's inbox by deleting your own. Gmail will treat a message as a thread. So if you have a message in the inbox and also have stored it in a particular label, deletion of that message from the inbox leads to deletion from label.
However, it does not remove from your friend's Facebook inbox, it's that simple.
