What are some alternatives?
When comparing Google Groups and Matrix.org, you can also consider the following products
GroupSpaces - Free Group Website, Membership Database, Listserv Mailing List, Online Group Management Software : GroupSpaces
Riot.im - Open source interoperable collaboration app.
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Slack - A messaging app for teams who see through the Earth!
Basecamp - A simple and elegant project management system.
Skype - Stay in touch with your family and friends for free on Skype. Download Skype today to chat and call on desktop and mobile.