Windows Live Groups

Windows Live Groups is an online service by Microsoft as part of its Windows Live range of services that enable users to create their social groups for sharing, discussion and coordination.

Features
The service will allow users to form their own community groups, similar to the way Facebook Groups function, allowing members of the group to participate in group discussions. In addition, Windows Live Groups integrates with the following Windows Live services to provide collaboration and sharing features:
 * Windows Live Calendar provides a group calendar function which allows all members of the Group to add or keep track of calendar events for their Group
 * Windows Live Messenger allow users to create Groups (not to be confused with "categories" in Messenger) in their contact list and start conversations with these Groups
 * Windows Live SkyDrive provides members of the Group to upload and share their files and documents for others in the Group to download
 * Windows Live Photos allow members of the Group to upload and share their photos with each other
 * Windows Live Hotmail provides users to send mass group e-mail messages to all members of a particular Group they are part of

History
Windows Live Groups was released on December 2, 2008. MSN Groups, a similar offering from Microsoft, has been discontinued on/after February 21, 2009. However, contents from MSN Groups could not be migrated over to Windows Live Groups, due to the different focus between the two products. The Windows Live Groups service is optimized for small groups like clubs or families, whereas MSN Groups caters to a wide variety of group sizes and types, including large public groups. Windows Live Groups was updated to the "Wave 4" release on June 7, 2010.