My girlfriend's mom went through our facebook messages?

[kujaava]

only if your messages contain some sort of statement about the message being confidential and only intend for the .. actually i'm not explaining, you could if something like this was at the bottom of the message

"This e-mail and any attachments thereto, is intended solely for the person or entity named herein and may contain confidential and/or legally privileged information. If you are not the intended recipient of this e-mail, you are hereby notified that any review, dissemination, copying, printing or other use of this e-mail, and any attachments thereto, is strictly prohibited. If you have received this e-mail in error, please contact the sender immediately and permanently delete the original e-mail, its attachments, any copy of the e-mail, and any print out thereof."