GroupMe

GroupMe is a free group messaging service offered by Microsoft. It supports groups of up to 500 users across iOS, Android, Windows 10, the web and SMS. Microsoft's introductory page is here.

It’s simple to add anyone to a group using their phone number or their email address. If they're new to GroupMe, there’s no need to download an app right away. They can start messaging over SMS immediately.

You can even use GroupMe to hold a conference call or conduct polls.

Many organizations such as schools and churches have used GroupMe for communication.

For myself, I use the SMS delivery so the messages show up in my phone's text messaging app. I change the text tone to differentiate GroupMe messages from other text messages.

Under the covers, GroupMe is pretty clever. Each GroupMe group is assigned a phone #. This is how the SMS and conference call features work.