I think this is the natural progression of the internet. It democratizes information and lowers barriers like nothing before. I am on Robinhood (just finishing up with adding funds). I have been on a quest for the right brokerage this year and have tried Vanguard, Fidelity, Etrade, TD Ameritrade, Motif and now Robinhood. All have various pros and cons. I think I will not be using Robinhood very much, but I am not their target audience (older and have more money to invest than a starting out 20-something). But, I love the idea. I received three automatic referrals when I joined and sent them to young folks I know that are just starting out. Helping the wiper snappers as only a Mustachian can :*)
I actually think Merrill Edge (with 30 free trades a month and excellent research available + other bank services) may be my final home, I also really enjoy E-trade and they have been very accommodating. They have offered free services and lowered my commission as I have become more active. Cheers.