TidyHQ - Organization management tool to support membership, subscriptions, event planning, and outreach.

doo - A smart, simple app for reminders and to-dos

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

Purp - A smart to-do list and goal tracker app

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

Gone - An ephemeral to-do list