Users of hosted web-based applications implicitly trust that those applications, and the data that is within them, will remain active and available indefinitely into the future. When a service is terminated, for reasons such as the insolvency of the business that is providing it, users risk the immediate loss of software functionality and may face the permanent loss of their own data. This paper presents Micasa, a runtime for hosted applications that allows a significant subset of application

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... gic and user data to remain available even in the event of the failure of a provider's business. By allowing users to audit application dependence on hosted components, and maintain externalized and private copies of their own data and the logic that allows access to it, we believe that Micasa is a first step in the direction of a more balanced degree of trust and investment between application providers and their users.