Joe Tsai, now a billionaire investor and co-founder of Alibaba Group, once admitted that his first exposure to Jack Ma's vision for the company was anything but clear—but he backed the idea anyway. A Startup With No Revenue and No Incorporation In a conversation posted on Stanford Graduate School of Business' YouTube channel in February, Tsai recalled meeting Ma in 1999 when Alibaba was still in its infancy. At the time, the company wasn't even …