GroupServer

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

Astraweb

Premium Unlimited Usenet news server services.

Email Marketing List Manager

Your own business messenger.

Create email discussion lists

Free Group Website, Membership Database, Listserv Mailing List, Online Group Management Software : GroupSpaces

Librelist is a free as in freedom mailing list site for open source projects

MailChimp is the best way to design, send, and share email newsletters.

Mailman is free software for managing electronic mail discussion and e-newsletter lists.

Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.

Sympa is an open source (GNU GPL) mailing list management (MLM) software.

Organization management tool to support membership, subscriptions, event planning, and outreach.

Unison is a group communication tool that helps organizations connect and organize their people.

Wiggio is an online toolkit that makes it easy to work in groups. With Wiggio you can:

Online discussion boards from Yahoo!

Zoho Campaigns is an email marketing tool with CRM & social media integration to help you create, send and track effective email campaigns.

Email analytics made simple. shiftmail provides a REST API and web interface for intelligence gathering within email marketing.