This excerpt taken from the EBAY 10-K filed Feb 28, 2007.
Global Community of Buyers and Sellers
We have aggregated a significant number of buyers, sellers, and items listed for sale, which, in turn, has resulted in a vibrant online commerce environment. Our sellers generally enjoy high conversion rates and our buyers enjoy an extensive selection of broadly-priced goods and services. Key components of our community philosophy are maintaining honest and open marketplaces and treating individual users with respect. We seek to maintain the satisfaction and loyalty of our buyers and sellers by offering a variety of community and support features, such as announcement and bulletin boards, customer support boards and personal pages, as well as other topical or category-specific information exchanges. By applying a consistent set of policies to our community, we seek to create a level playing field that lets individuals and businesses of all types and sizes access broad markets and compete equally.
Our success has resulted largely from the growth of our community of confirmed registered users, which has increased in size from approximately two million at the end of 1998 to approximately 222 million as of December 31, 2006. As of December 31, 2006, we had approximately 82 million active users on the eBay.com platforms, compared to approximately 72 million at the end of 2005. We define an active user as any user who bid on, bought, or listed an item during the most recent 12-month period.