I think what Bitcoin Trader had going for it was a 'Degree of plausibility'   When you looked at it at first glance, you would think "I can see how that could work"  Particularly back in the days when MT Gox  was trading 100 dollars above everyone else.. 

If you built a spreadsheet and tried to work out how the arbitrage would work - it didn't add up -- but who does that?Once you are in, you want to believe what you want to believe, and many people would lie to themselves and everybody else at least long enough to get their money out..

Esoteric came in and pretended to be a legit BT --  I don't think many believed them -- thus the short lifespan..  Hopefully everyone has learned their lesson.  I think several of the "Cloud Hashing" services are also HYIP..  So there will be at least one more round of "Where's all our money"  Hopefully by then most will have learned their lesson and will be ready to pass along their advice to most anyone who asks..