Related to this question:
I'm looking for a list of archived public mailing lists from diverse communities and in diverse languages.
For example, a list would look like this:
www.fake-link.com, Debian Linux
www.fake-link.com, Bird Watching group
www.fake-link.de, Fans of Berlin
www.fake-link.de, Photography club
and so on (und so weiter)
One way would be to find these mailing lists, and to create a list of them, would be to use clever google searches for things like Pipermail, and other mailing list software
A great structure would be .mbox, but it's not necessary.