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Clicking on the Calendar in the Group's landing page, they can learn more about the specific event (such as date, location and comments/updates)
Analysis
Learnability : This interface is learnable due it's simple interface that's similar to most forum style websites, maintaining external consistency. The interface focuses on larger group activities and makes it easy to find groups based on certain criteria.
Efficiency : In terms of efficiency, the interface might be limited by it's forum/blog style approach. Though, the user gets a brief overview of each group in the search results,they they are still required to visit each group's page to learn about activities and schedules. It's not easy straight forward to schedule individual activities with specific members.
Safety : The scope for mistakes is fairly limited for users since they don't have permissions to make changes to Groups, since only the admin/group owner will have permissions to edit them.Individual comments posted can be edited.
This interface might be limited by it's lack of visuals which might make it un-intuitive to users not familiar with forums and blogs (though a small user population).