This excerpt taken from the EBAY 10-K filed Feb 28, 2007.
Our focus is on key operating and financial metrics
Members of our senior management team regularly review key operating metrics such as registered users, active users, listings, gross merchandise volume, eBay stores, total accounts, active accounts, total number of payments, total payment volume, and transaction rates. Members of our senior management also regularly review key financial information including net revenues, operating income margins, earnings per share, cash flows from operations and free cash flows, which we define as operating cash flows less purchases of property and equipment, net. These operating and financial measures allow us to monitor the health and vibrancy of our Marketplaces, Payments, and Communications segments and the profitability of our business and to evaluate the effectiveness of investments that we have made and continue to make in the areas of marketing, product development, international expansion, customer support and site operations. We believe that an understanding of these key operating and financial measures and how they change over time is important to investors, analysts and other parties analyzing our business results and future market opportunities.