Prior to joining Zappos, Hsieh co-founded and sold the internet advertising network LinkExchange to Microsoft in 1999 for $265 million. Members were allowed to advertise their site over LinkExchange's network by displaying banner ads on their website. By 1998, the site had over 400,000 members and 5 million ads rotated daily. In 1999, Nick Swinmurn approached Hsieh with the idea of selling shoes online. Hsieh was skeptical and almost deleted Swinmurn’s voice mail. After Swinmurn mentioned that "footwear in the US is a $40 billion market