That's what I find so perplexing about this patent in particular – email is only useful due to interoperability, so patenting the underlying representation of an email is a non-starter for general purpose use.

I really hope you don't have general purpose use in mind, I'm guessing you're hoping it's more for something along the lines of EDI applications between governments, or something else. I just don't get what it's for.

At risk of going blue in the face, where is the value in this patent that I'm not seeing?