20. The computer-readable storage device of claim 19 , the operations further comprising: determining an output type for predictive output for the client-subscriber computing system, wherein: if the output type is included in the request, then determining the output type comprises receiving the output type in the request; and if the output type is not included in the request, then determining the output type comprises determining from the information that describes each of the trained predictive models that one or more models included in the predictive model repository are compatible with the one or more input types determined from the request to input types and that the one or more models can generate output of one or more output types, and selecting the output type from the one or more output types.
19. A computer-readable storage device encoded with a computer program product, the computer program product comprising instructions that when executed on one or more computers cause the one or more computers to perform operations comprising: receiving a request from a client-subscriber computing system for access to a trained predictive model from a repository of trained predictive models, which trained predictive model can generate a predictive output in response to receiving input data having one or more input types, wherein the one or more input types can be determined from the request; determining from information that describes each of the trained predictive models in the predictive model repository that one or more models included in the predictive model repository match the request from the client-subscriber computing system, wherein determining a match is based at least in part on a comparison of the one or more input types determined from the request to input types included in the information that describes the trained predictive models; and providing access to at least one of the one or more models to the client-subscriber computing system; wherein the one or more models that match the request are models that were trained using training data provided by a computing system other than the client-subscriber computing system.