>They also maintain whatever threading is in operation (individual messageboards at least).
> The BBS email interface can't do this.
Huh? Email readers handle threading easy. I'm on dozens of email lists, my mail reader (netscape) sorts each list into it's own folder and sorts the messages within each folder by thread. Even for the maillist version of this BBS where many of the messages are not directly replied to in a mail reader, but rather sucked out of a proprietary web BBS interface, netscape still handles the threading OK.