margaret vester prepares for a summer finale to her five-year crackdown on u.s. tech giants.ut first, to our top story, big tech in the eye of the storm on capitol hill. facebook, amazon, apple, google, all appearing in washington to answer lawmakers' questions. the first to be baked over the raked over the coals, facebook's david marcus was the -- david marcus. the co-creator of the cryptocurrency project. senator brown: facebook is dangerous. now, facebook might not intend to be dangerous, but surely they do not respect the technologies they are playing with, like a toddler who has gotten a hold of a book of matches. their motto is to move fast and break things. we would be crazy to give them a chance to experiment with people's bank accounts. david: we will take the time to get this right. wouldn't it be easier and safer if people could inexpensively secure money transfers through their smartphones just like they do for so many things today? that is what libra is about. >> i do not trust you guys, so instead of cleaning up your house, now you are launching into another bus