Mighty Networks - Mighty Networks enables entrepreneurs, organizations, and companies to create and grow a community-powered brand.
Google Groups - Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.
Meta Search - Search your Desktop, Google Drive, Dropbox, Gmail, Evernote.
Groups.io - Email and web based discussion group software, includes archiving, emails, wiki, polls, file...
Community Box - Easily create beautiful directories
Gaggle Mail - Gaggle Mail is a simple and easy to use email list manager.