Facebook's David Marcus: What bots can do for you

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 into a commerce engine. This week, Marcus did a major overhaul of Messenger.