Julie commented "But wouldn't a wiki be cooler than just searching the message archives? Or maybe adding tagging like delicious?"
Cooler, yes, but less accessible if you're using dial. What, you think EVERYONE has a broadband connection? Not so, and a number of listserv subscribers are connecting from locations where a broadband connection is either not available or not affordable.
I think it would be a loss and a shame to exclude those subscribers.
Best regards.