How I Built This with Guy Raz

The Knot: Carley Roney & David Liu

When Carley Roney and David Liu got married, they had a seat-of-the-pants celebration on a sweltering Washington rooftop. They never planned to go into the wedding business, but soon saw an opportunity in the market for a fresh approach to wedding planning. In 1996, they founded The Knot, a website with an irreverent attitude about "the big day." The Knot…