Communication often is nullified ...

"Many attempts to communicate are nullified by saying too much." -Robert Greenleaf

This can be applied to many aspects of communication, sometimes evens with data there is more sent that often may be necessary.  Yet in the modern society where so much deals with authentication email messages have become quite bloated with overhead that deals with authenticity of the message / message sender.

What happens when a low-speed network is needed to complete the delivery?  Will the message delivery be delayed because of the overhead.  What is the solution?

What prevents spread spectrum technology from being used on High Frequencies (HF)?  There's some work being done on UHF (70cm) that will help in regional delivery of messages.  What will it take to make this technology more wide-spread?