Windows Live Groups is an online service that allows users to create groups for sharing and collaboration.
Anyone with a Windows Live account can create a group. You can even customize the name, avatar, status, email address, and theme of your group.
Sending an email to your group is easy. From Groups, it will automatically redirect you to Hotmail with the group email address in the To: box already.
You can share documents like Word, Excel, PowerPoint and even OneNote files to your Group. Those without Office installed in their desktops can still open documents online through Office Web Apps. Each group also has a SkyDrive with 5GB space.
There is also a calendar where you can add events. You can sync it with your calendar in Outlook or Windows Live Mail.
You can start conversations with Windows Live Messenger.
Try Windows Live Groups to share and collaborate easily and effectively!
CEEESQUARED'S BLOG 
Sakura Science
June 5, 2011
I had a group, and I started it a while ago. I was able to have discussion with other members on the website. I have since started a new group today, but I can’t find how to start a discussion or make a comment. Can anyone help?