In yesterday's show we talked about how advertisers are not leaving Facebook. But lots of them are migrating from Facebook proper to another platform it owns: Instagram. One analyst estimates that ads on Instagram will account for 70 percent of Facebook's new revenue by 2020. And the most exciting thing for the company is Stories, the little posts that expire after 24 hours. Instagram may have stolen the idea from Snapchat, but it's working. There are even Stories on Facebook now. Mark Rabkin is vice president of ads and business platform at Facebook. In the second part of his conversation  with host Molly Wood, he says people are posting over a billion Stories a day, and advertisers better get on board. Today's show is sponsored by Pitney Bowes and Indeed.