Yes I think this is going to be a huge disruptor entrant into the brokerage space.Robinhood will be very successful and maybe even cause the other brokers to suffer some serious damage.
I can see them getting a few million total accounts to sign up eventually.
I do not care if you are trading a 100K account or a 1K account, the fact is that if you can save 1000 to 10K a year in brokerage commissions, why not go for it ?
The arguments people make that they will somehow sell their order flow to other market makers and give you a bad execution price needs to be examined carefully. However, I think for small accounts just starting out the slightly worse execution price is a NON issue in my opinion.
robinhood allows anyone with even only 10 dollars to start, to try to grow it into much larger amounts through trading.