Re: A couple of comments on the open issues...

   First a question: Is subadressing just something that is done
   by a few email systems locally, or is it something specified
   in some of the email standards? 

It's not specified in any standard that I'm aware of, but it is
functionality that is provided in many Unix MTAs.

   Also, using subaddressing seems to be quite popular for high-end users.
   But is it actually very much used by the bulk of users (the
   proverbial hotmail/yahoo/... crowd)? My guess would be that it's not.

Probably true.

   If that's the case, then this may give us some slack, because as
   far as I understand, the main push for internationalized addresses
   is from average users, not necessarily high-end users. It's also
   easy to imagine that users have a single internationalized
   address (for personal mail) and a bunch of structured addresses
   (for list subscriptions,...).

I guess.  But it would be nice if high-end users could use IMAs with
subaddresses if they wish.

   A third thing I have just thought about is that the design of
   punycode actually has some very nice properties that allow
   separation of the subnet address in most cases even if the whole
   LHS is encoded in one go.

The problem here is that you don't want to change the MTA.  The MTA
uses a particular algorithm for spliting the address into mailbox and
subaddress, and it would be nice if IMAA didn't break it.

	    -roy