This presentation introduces RealNames, one example of a common name resolution service. The first part of the talk identifies the requirements established by the market deployment of RealNames from the perspective of users, browser makers and search engines, and also from the perspective destinations, trade name holders, and content providers. The second part of the presentation focuses on the technical architecture of the RealNames system, including various design choices for scalability, response time, maintainability and fault tolerance. Lastly, some thoughts are given on the future role of common name namespaces as part of the Internet infrastructure.