The Keynote Online Retail Web Transaction Performance Index – Books & Music measures the performance and availability of going to a selected retail books-music-video site to search for an item, adding it to the shopping cart, and proceeding to check out without logging on to an account. All measurements are taken from the ten large U.S. metropolitan areas (Boston, Chicago, Dallas, Detroit, Houston, Los Angeles, New York, Philadelphia, San Francisco, and Washington, D.C.) on high-speed links attached to key points on the largest U.S. Internet Service Provider (ISP) backbones. The category focuses on the Books & Music vertical in the online retail industry.