[eries]

An analogy: any software company is free to build their own custom protocol, no problem. Nothing stops them from doing their own hyperlinking thing now. If they aren’t building it on existing applications, why do we need the WWW?

[vasilipupkin]

not a great analogy. There is no new protocol required to trade stocks, right? Companies already issue different classes of stocks with different rights. GOOG vs GOOGL or Viacom VIA vs VIAB. It's not a technology issue, it's a legal / regulatory issue. Because of Reg NMS, your exchange will get some volume but I don't see what value it creates beyond playing regulatory arbitrage.