we had an opportunity yesterday to have the very first investor in robinhood, tim draper -- the whom came on, and we said to him shouldn't we worry about the fact that owl the revenue -- all of the revenue comes from that one source? here's what he said and then i'll let you react. >> wait a second. [laughter] you've got -- but facebook's a trillion dollar business, and all of their revenue comes from advertising. wouldn't you say they're at risk because their business all comes from one place? no, absolutely not. and order flow, that data's going to be very valuable to very many people for many, many moons to come. and it allows robinhood to continue to provide free trading, and i think that's just fantastic. liz: yeah, until somebody like sec chair gary gensler comes in, right, karl, and says we don't like this payment for order flow model. >> i think the only difference there is i haven't heard that advertising is at risk from regulatory intervention is. liz: exactly. >> i would just say payment for order flow in general, and i think a while back if you go back to ken griffin's te