Invision Community - Invision Community is a flexible, integrated set of apps for building communities on the web.
Google Groups - Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.
XenForo - Intuitive. Social. Engaging. Fast. XenForo brings a fresh outlook to forum software.
Membee - Membee is web-based membership management software.
Mobilize - Mobilize is a scalable messaging app built for large groups.
Galette - Galette is a membership management web application towards non profit organizations.