Everyone is/should be aware of ponzi schemes, I am, but I did take a punt on coinfactory.  I don't mind a punt or 2 now and then.  I invested while being aware the site would fold at some stage.  Fortunately for me I did receive all my original investment back as interest (plus a couple of days) before the site went ass-up.  Last few days it has not been paying, so I assume they have done a "runner" now.