Facebook Messenger chief David Marcus on chatting with bots

David Marcus, who heads Facebook's Messenger platform, tells Jefferson Graham how automated chat bots can improve the shopping and customer service experience, on #TalkingTech. SAN FRANCISCO -- Clicking a buy button on a website is so 20th century. Now the next big thing is conversing with a computerized robot. Used by 900 million people, Messenger has a major new look and mission, thanks to former PayPal chief David Marcus, who left the payment giant in 2014 to transform Facebook's hugely popular Messenger app. This week, Marcus unveiled the next big move for Messenger.