| http://groupbox.com/ |
| http://www.groupsite.com/ |
| https://groups.google.com |
| http://groupspaces.com/ |
| https://voicethread.com/howto/creating-groups/ |
| https://docs.moodle.org/23/en/Groups |
| https://www.flickr.com/groups/ |
| http://manual.mahara.org/en/1.5/groups/create_group.html |