Tribe.so - Tribe is a white-label platform, empowering the new generation of online communities.
Google Groups - Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.
Higher Logic - Private, secure online communities that stimulate conversation and ignite engagement.
Galette - Galette is a membership management web application towards non profit organizations.
Discourse - Discourse is an open source discussion platform built for the next decade of the Internet.
Bigtent - BigTent is a web-based organization and communication portal for groups.