You started Birchbox with a friend, Katia Beauchamp. How do you make a business partnership work?

We made sure that we were aligned. A lot of people, when they're excited about an idea, don't realize that their partner actually wants it to be totally different. We also got the paperwork out of the way first--questions like "What happens to your equity if you are no longer working full time at the business?" It's almost like having a prenup before you get married. 

You and Katia share the CEO title. What does that mean practically?

We knew that to scale, we would have to divide and conquer. Now I'm responsible for more of the internal functions--tech, product development, operations--and Katia is responsible for external functions, like PR and business development. We always say that we could do each other's job, but we just wouldn't do it as well.

Birchbox started out selling women's beauty products. How did you try to appeal to men?

We were concerned that it would be harder to go viral--that guys wouldn't turn around and tell 10 of their friends, "Ooh, I got this new moisturizer I love at Birchbox Man." So we began including lifestyle products, like sample headphones and pocket squares. Guys seem a little more comfortable being like, "These cool earphones. Got them at Birchbox."

You started online, but now you've opened a traditional store. Should more e-commerce companies go brick-and-mortar?

Less than 10 percent of beauty products are purchased online. We don't kid ourselves--it's not going to be like books or music, where it's 90 percent-plus online. You want to touch and try our products in person, and we need to understand that to grow. So we haven't changed our approach. It's more that we're finding different angles into it by opening a store.