was legal and that he had no idea that information would be used to help donald trump's 2016 campaign. investors are suing facebook in the wake of the scandal, sending the company's stock plunging almost $50 billion this week alone. let's bring in cnn sarah murray. how important was this data? the firm, cambridge analytica, to the trump campaign? >> conflicting accounts to this. we've obviously seen all of these undercover videos where you see the cambridge ceo, alexander nicks taking credit for that from channel 4 in the uk. saying we never bought a notion into this psychographic method. instead we would use them for polling, to create models to help us decide where to send president trump for rallies. these were not the key data players in our campaign. that was the republican national committee. >> facebook is facing a lot of questions on how they protect users' privacy. what are they saying about that?