One piece of the "Robinhood Abstraction" that is popping up a lot right now is that the fact that a large majority would have been using margin, but not known it.

Much of the nice and fast experience that Robinhood offers ("Just signed up? You can start trading!", "Initiated a transfer? Start trading now!", "Just sold something? Rebuy something else immediately!") are all powered by the fact that these are all technical using margin.