Probably very little, only "non printable" (in particular the bell) should
be disallowed.
On the topic of wwcn and internationalization: support for more than one
charset would be of great interest for everybody who does not solely use
latin-1. This includes the use of greek and mathematical symbols, chinese
japanese, braille or even klingon.
At first i only thought about usage of iso or unicode for the non-conver-
sational part (such as a nickname and a realname) but this could even
extend to the actual conversation. Unfortunately i don't have a clue as how
feasable or desirable this would be. The main question seems to be if people
in the same context (channel) are going to use different charsets.
Jan.