The only site to let you bulk-invite people to your group. The only site with a personal and a group calendar. Hard for visitors to find an active public community to join. Polls are easy to set up and provide a good deal of info. No chat room for team collaboration.
Site is graphics-heavy, which makes it slow to download.
Difficult to find features without left-hand frame list that most others use. You can't set as many polling features as at eGroups. Uses eGroups for its mailing lists. 10MB free Web space to build pages around the calendar, discussion boards, and other features. Default welcome page is blank.