My guess is Calacanis gets lots of notifications and he probably just missed it. The group creator controls when the group is made public, and given Facebook's

My guess is Calacanis gets lots of notifications and he probably just missed it. The group creator controls when the group is made public, and given Facebook's track record, you should probably assume anything you write in Facebook (except private messages) may eventually be public. Also I believe you can be "force joined" to non-private groups.