More than 9,000 eBay sellers, buyers, employees, developers, and vendors of associated products have descended on Boston for the 6th annual eBay Live! conference being held at the Boston Convention and Exhibition Center through Saturday. To mark the occasion we asked eBay to tell us a bit about how Bostonians use the site, which likes to call itself "the world's largest marketplace." Since eBay auctions $1,839 worth of items each second, it's a pretty good indicator of economic activity.