Internal memo by Nick Clegg says a whistleblower is expected to appear on Sunday's "60 Minutes" and accuse Facebook of contributing to US political polarization (Mike Isaac/New York Times)

Mike Isaac / New York Times:
Internal memo by Nick Clegg says a whistleblower is expected to appear on Sunday's “60 Minutes” and accuse Facebook of contributing to US political polarization  —  In an internal memo, Facebook defended itself and said that social media was not a primary cause of polarization.