[admin] New mailing list system

Dear subscribers,

In order to facilitate the work of the moderators of mailing lists,
and to make the W3C's mail archive policy explicit we have a new system
for our lists. Now when you send a message to a list you will receive
an automatic reply asking you to confirm that you want to post to that list.
If you specify so in your response, the system will remember your address
and will never prompt you again.

Max.