Amazon

Amazon

www.amazon.com
Unique visitors, January 2009: 51,220,000 (Nielsen Online)

Amazon (AMZN) lets you list products in its massive catalog that will show up when customers search on the site. The company also offers other e-commerce services like Amazon WebStores and Amazon Fulfillment.

Pros: A presence on Amazon can establish credibility with shoppers unfamiliar with your brand.
Cons: Listing on the site means your products and prices will be displayed alongside competitors who also sell there, and offerings from Amazon itself.