Google Groups - Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.

EventTitans - Top rated event management software

Galette - Galette is a membership management web application towards non profit organizations.

Tix - Tix is a state-of-the-art, cloud-based ticketing system that features fully integrated access controls, event management controls, multi-channel distribution capabilities, and a robust reporting suite.

Bigtent - BigTent is a web-based organization and communication portal for groups.

Brushfire - Brushfire offers tools for online registration and event management.