Thanks for your reply.
Maybe I'm not understanding promoted properties correctly, but I don't think that's what I need.
I have a dropdown with 7 choices. For each of these options, there's a corresponding text box. I've got the conditional formatting working right so that when a dropdown choice is made the matching text box appears; but, when the form gets submitted ALL of the text box fields get posted...not just the one corresponding to the chosen dropdown.
What do I need to set to tell InfoPath to only submit the text box that matches the chosen dropdown choice?