Poshmark is an app where you can either buy items from other users or try to sell unwanted items like clothes, handbags, shoes, or home decor. Think of eBay, but with more social aspects where people could follow each other’s “closets,” and comment or share the listings they like. It started bak in 2011, and has grown to 50 million users and paid out more than a billion dollars to sellers. We talked with CEO Manish Chandra about his fashion magazine background, this year’s decluttering trend and how he kept the company from growing too fast.