Unsolicited data scientists solving your problems without using your data

I love this post by +Vincent Granville on Data Science Central.  In the top part he looks at the problems experienced if you post to LinkedIn regularly, but he has links to to other problems that need answers further down the page.

With reference to the discussion about estimating the number of bogus accounts on Facebook there is no mention of the various games played on FB.  I know that many people that play them have multiple accounts in order to help as many FB friends as they can.