I’ve always wanted to write a script to get a message’s link to refer to it easily from my notes in Evernote or basically anywhere else. Things does that when creating a todo directly from within Mail.app and adds the link to the todo’s notes.
As expected, such a script has already been written. By John Gruber, in this case. Works like a charm.
Unfortunately, it does not seem to work on iOS. Pasting such a URL into Safari’s address bar results in an “Cannot Open Page” alert.