GNU Mailman is a mailing list management software. Mailman project was started long time ago before the Millennium. Since its birth it has become the most intelligent tool for handling mailing lists ever. Huge number of companies with Fortune 500 members among them have been using Mailman for years. The new version Mailman 3 brings to us even better user experience and communication power.
Mailman - Mailman is free software for managing electronic mail discussion and e-newsletter lists.
Google Groups - Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.
Sympa - Sympa is an open source (GNU GPL) mailing list management (MLM) software.
TidyHQ - Organization management tool to support membership, subscriptions, event planning, and outreach.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
Mighty Networks - Mighty Networks enables entrepreneurs, organizations, and companies to create and grow a community-powered brand.