Green Dot was an interesting company to me. I knew a lot of people in poor and working class communities that benefited from it. Its proposition was simple with straight-forward benefit and small, easy-to-understand cost. No chance of getting in endless spiral of debt either that hit many impulse buyers. eBay friendly. Got big or dominant. Hard to tell as outsider given every company has cards these days.
Sharon, is there a good write-up on how they showed up, marketed themselves, and expanded to get to their level of success? I think lessons learned might help in many other ventures, including YC's payment investments.