This was actually asked/answered last night.
There isn't an extension currently but a special page could be written that grabs email addresses from the user table and sends out a notification.
DSig David Tod Sigafoos | SANMAR Corporation PICK Guy 206-770-5585 davesigafoos@sanmar.com
-----Original Message----- From: mediawiki-l-bounces@lists.wikimedia.org [mailto:mediawiki-l-bounces@lists.wikimedia.org] On Behalf Of Tim Ware Sent: Thursday, June 21, 2007 14:00 To: MediaWiki announcements and site admin list Subject: [Mediawiki-l] Email Notification for MW 1.9.4?
Is there a good extension for sending an email to all our registered users?