Snapchat CEO Evan Spiegel’s hands are shaking as he points to his iPhone. He’s unmistakably nervous, and not in a sweaty, early-Mark Zuckerberg kind of way. There must be a lot on his mind as the young CEO of a company bounding toward a $1 billion valuation — a company that has changed the course of being a teenager in the year 2013. Spiegel brushes off Snapchat’s latest bragging right: the service sees 350 million snaps sent per day. He seems anxious, as if he’s about to interview for a job or deliver a commencement speech to his graduating class. Instead, he tells me about Stories, his team’s latest invention: a rolling compilation of snaps from the last 24 hours that your friends can see. You create your Story as you go about your day by tapping “My Story” above the friends you want to send a snap to.