As explained to you in another HN post. HN makes their money via their margin accounts aka Robinhood Gold, and by selling their order flow, like many other brokerages do. It results in better execution for the clients (like myself) and a tighter spread. If it means I get a better price and someone else gets first dibs at the buy or sell side, I honestly don't care. You can use limits if you worry about getting "ripped off by the man".