Entrepreneurs in record numbers are setting up shop on eBay, according to a recent survey conducted for eBay by ACNielsen Media Research International. More than 724,000 Americans report that eBay is their primary or secondary source of income. In addition to these professional eBay sellers, another 1.5 million individuals say they supplement their income by selling on eBay, according to the survey. In recent years, eBay members in the United States...