I think Verner Vinge's A Fire Upon the Deep describes a teleconferencing system based on avatar models combined with the receiving side's video image history of

I think Verner Vinge's A Fire Upon the Deep describes a teleconferencing system based on avatar models combined with the receiving side's video image history of the sender. It really had nothing to do with the story, other than a technical detour about ship-to-ship communication. The novel also had a galaxy-spanning Usenet-like system that was part of the story. :)