Sesame Database Manager - Lantica Software, LLC - Sesame, A Q&A-compatible Database Manager.
TidyHQ - Organization management tool to support membership, subscriptions, event planning, and outreach.
Sheep - Membership and events for SMEs and nonprofits
Galette - Galette is a membership management web application towards non profit organizations.
CentriQS - CentriQS offers small business management software and custom database solutions for small and medium enterprise businesses.
Google Groups - Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.