PlanetLab is an experimental global network of computers designed to enable researchers to develop and test powerful new types of software that can operate across multiple computers, treating the global network as a single, large, distributed computer. This approach supports the emerging class of geographically distributed network services by providing an overlay-based testbed that allows researchers to design, evaluate, and deploy these services. Unlike traditional network testbeds, PlanetLab supports both service developers and client users, leading to four key design principles: continuous operation, distributed resource control, unbundled overlay management, and application-friendly APIs. The talk outlines this vision and updates on the progress and plans for implementing it in PlanetLab.PlanetLab is an experimental global network of computers designed to enable researchers to develop and test powerful new types of software that can operate across multiple computers, treating the global network as a single, large, distributed computer. This approach supports the emerging class of geographically distributed network services by providing an overlay-based testbed that allows researchers to design, evaluate, and deploy these services. Unlike traditional network testbeds, PlanetLab supports both service developers and client users, leading to four key design principles: continuous operation, distributed resource control, unbundled overlay management, and application-friendly APIs. The talk outlines this vision and updates on the progress and plans for implementing it in PlanetLab.