[MT] Are my tags confidential?

MailTags lets you share message tags to create an informal workflow with your recipients.

To keep your tags confidential and not pass them on to others it is important to know how MailTags stores its information in an 'X-header'.

How tags are stored when you are composing a message:

When you tag a message in the composer, the tags are stored ONLY in your copy of the message for future reference. The tags are NOT conveyed in the the headers to the recipient. Unless.... You elect to send the tags in the message by check on the "Include in Sent Mail" checkbox in the MailTags panel.

You are free to test this with a couple of test messages to your self.

How tags are stored when you reply to a message:

When you reply to, forward, or redirect a message, Mail will automatically strip the headers of a previous message when replying and forwarding a message. Accordingly, any tags set on a message you reply to or forward will not be conveyed to the recipients.

Again you can test this by tagging a message and forwarding it to yourself.

Note: if you use a Mail Client other than Mail (eg web mail, thunderbird etc) the handling of original headers of a message depends upon the Mail client. For example, some will include the entirety of a message (headers and all) as an attachment when forwarding an email.

For a future version of MailTags Scott will look at the possibility of encrypting tag data in the headers.