Please have a look at Gmane.org[0] - they and many, many others archive mailing lists. Mailman also comes with a built-in archiving solution. Open Source software like hypermail helps you building web sites from Mbox-files.
cheers Simon
Ok, Simon,
You are making a really smart point here. But I still think my question is a valid one: Should we start up a Google group, named something like MediaWiki-Community?
The fact that you or others don't need it doesn't really answer the question. Does somebody need it?
For those not familiar with Google groups, they are similar to Yahoo groups, only less commercial (looking) and with other friendly advantages. My arts community in Baltimore likes Google groups.
Richard http://BaltoCo.org/contact