Smartphones have enabled investing to reach the masses, driven by the viral growth of the Robinhood Markets trading application. It now has over 25 million customers and was only incorporated in 2013. Everyone knows about Robinhood, but another disruptive stock brokerage platform is gaining rapid share of the investment community, coming at the industry from a different angle: Interactive Brokers (IBKR 2.20%).Known as IBKR for short, the company has grown its client equity at a rapid rate over the last deca ...