There was a time not so long ago when it seemed like the most consequential conversations in our society were happening on social media. But as the digital commons spawned mobs, performative posturing and rage-baiting, a lot of those conversations went private. That's one takeaway from the recent Semafor report on the private group chats between tech titans, business leaders and public intellectuals. Marketplace’s Meghan McCarty Carino spoke with Amy Webb, founder and CEO of the Future Today Strategy Group, about the growth of what she calls the Splinternet.