Based on what I'm seeing, I don't think that's the case, Caeli. I've made several contributions on "Talk" or "Discussion" pages and have nothing showing up on "My Talk". My guess is that the "My Talk" is the same as the "Discussion" tab on your User page, but acts as a system to let you know that a change has been made to the latter.
If it's never been edited, the Discussion tab and My Talk should be red.
I've been using the Discussion tab/Talk page to send messages to Users, especially when they have different usernames on Elliquiy and Elliuiki.
Just tested it with my own page, and that is indeed how "My Talk" works.