Simple question, or is it...

It’s you who can’t keep it straight. The signal is not the Poynting vectors. 

I don't think anyone uses transmission lines for interconnects or speaker cables. 

Oh, brother! 😧 Well, something’s being transmitted!

Well that's where Poynting vectors come in, transmission lines. 

Huh? Then maybe you can tell me if this is where all those guys get their info. 
An excerpt from Wikipedia,

Coaxial cable[edit]Poynting vector in a coaxial cable, shown in red.

For example, the Poynting vector within the dielectricinsulator of a coaxial cableis nearly parallel to the wire axis (assuming no fields outside the cable and a wavelength longer than the diameter of the cable, including DC). Electrical energy delivered to the load is flowing entirely through the dielectric between the conductors. Very little energy flows in the conductors themselves, since the electric field strength is nearly zero. The energy flowing in the conductors flows radially into the conductors and accounts for energy lost to resistive heating of the conductor. No energy flows outside the cable, either, since there the magnetic fields of inner and outer conductors cancel to zero.