No two companies have defined the e-commerce space more than eBay Inc (NASDAQ: EBAY) and Amazon.com (NASDAQ: AMZN), especially as both emerged at the dawn of the Internet. With its auction-based marketplace, eBay was the early leader in online shopping, while Amazon has expanded from offering books to selling essentially every retail category, borrowing eBay’s marketplace model along the way. Today, it’s the clear leader in e-commerce.