I have so many questions. Sound-based thought waves? The galaxy has speed zones? Ultimately though it was such a good story that I don't care much about the answers. I was super impressed by (since he was writing in 1993) and absolutely love Vinge's idea of a galaxy-wide internet that's hundreds of millions of years old and nobody knows who started it. That to me seems extremely plausible, given a universe with multiple sentient space-faring species. This was SO much fun, and anyone who loves science fiction should definitely read it.