[mayutana]

The reason for Facebook's popularity is its simpleness. Now that it is popular, it can experiment with additional features such as groups and more intimate group settings. Orkut, on the other hand attempted to do it the other way around. I am not sure how does it work now, but 2-3 years back, when one adds a friend, he is expected to rate the closeness in a scale of 1-5. This was to improve friend of friend suggestions as well as who is allowed to see what. The problem with this approach was that it was confusing for the users. This might be a stumbling block for new applications that try to foster a private group structure. But I do agree with Dave that there is a need for such applications.