Senators Grill Social Giants

Internet firms Facebook, Google, and Twitter face questions from Senators over alleged Russian influence on the 2016 US Presidential election. Plus, does blockchain technology offer a way to fix the "fake news" problem? We speak to the startup Publiq which thinks it does. And, we hear how you set up an ecommerce business in Somalia. Presented by Rory Cellan-Jones, with BBC Silicon Valley reporter Dave Lee, and tech journalist Kate Bevan.

(Image: (L-R) Colin Stretch, general counsel for Facebook, Sean Edgett, acting general counsel for Twitter, and Richard Salgado, director of law enforcement and information security at Google, testify to the Senate Intelligence Committee. Credit: REUTERS/Joshua Roberts).