Apparently you have to be vetted and invited to join, and there is a hefty initiation fee to join. There are poorer people joining who are the peons like secretaries and personal assistants, but they are sponsored by the rich and they can be traced. They are not allowed to have full profiles, just contact pages so that "my people can talk to your people".
I am told that this secret URL begins with an "X", and there is no login page. If you stumble upon the web page there is nothing on there. However there is a USB key that goes with it, and if the key detects the page, it securely logs you in.
Very intriguing. I can't tell you more.