All feedback is welcome.
If there's any questions or such you want to give me personally, use firstname.lastname@example.org.
There's no mailing list dedicated to m9u. For now, feel free to ask questions on 9p-hackers [archives], and if that generates too much traffic I'll set up a dedicated list (and be quite surprised :) ).
Again, there's no dedicated channel. #9p on freenode needs some love, so ask questions there.