The story of Zoom founder Eric S. Yuan is an entrepreneurial fable that proves even the most crowded markets are never truly full. Before launching his online conferencing and collaboration product, Zoom’s Yuan ran engineering for Cisco’s WebEx. He expanded the WebEx team from 10 engineers to 800 and grew revenues from $0 to over $800 million annually. Yuan was the heart of WebEx from 1997 to 2011, but he wasn’t happy. The product wasn’t good enough. Yuan (and many customers) thought it was slow, multimedia streams were often shaky, and it lacked modern features for mobile. For years, Yuan campaigned Cisco execs to let him rework WebEx and build video conferencing on the cloud, but the existing product was still earning serious cash. His bosses saw no reason to risk a reboot. So, Yuan left in 2011 to build Zoom. “Cisco made a mistake,” he recently told F orbes magazine. “Three years after I left, they realized what I said was right.” Was he ever. Zoom’s annu