Email lists, with an integrated web interface, and control.

Administering Large Mailing List Sites

Are you sick of the limitations of open source MLMs, but not ready to give up control to a web-delivered service?

Give Your Users a Web Interface

Let your users read and post messages and files, and configure their settings with a single web interface.

Keep Control of your Site

Install, customise and administer your site as you choose.

Download GroupServer 1.0β

GroupServer 1.0β is available for free download now.

GroupServer

GroupServer has an email interface like Mailman, and a web interface like Google Groups, but it's GPL.

GroupServer has been in production for five years. It is built by OnlineGroups.Net who provide hosted sites, as well as custom hosting and technical services.

There is a developers list and the issue tracker and repository are open.