It was in November that Amazon closed its $1.2 billion (at Amazon's current stock price) acquisition of mega shoe e-tailer Zappos. The three months may seem like ages ago, but the two companies are still in the early stages of integrating and learning from one another.

In this second part of my four-part interview with Alfred Lin, COO and CFO of Zappos and an entrepreneur known for being skillful at selling companies, Alfred talks about why Amazon bought the shoe e-tailer. Surprisingly, Amazon had little customer overlap with Zappos, said Alfred, making the acquisition a good fit. Alfred doesn't get into too many details about how Amazon is helping the shoe e-tailer go beyond footwear, but he said that Zappos is meeting with the buying teams in different product categories at Amazon and sharing their lessons.

Alfred also said that there were no other suitors when the deal came together. "We were just very focused on building our business," he said. But from the sounds of it, the two have been talking for a long time and the timing was finally right. 

"We’ve also known each other for a long time," said Alfred. "We had a comfortable relationship over time. It made sense this time around."

(Editor's note: Tony Hsieh, founder and CEO of Zappos, will be giving a keynote speech at Vator Splash May. Tony will be talking about how to build a business and have a billion-dollar exit).