8. A system comprising: data processing apparatus programmed to perform operations comprising: receiving input data and a request for a predictive output from a client computing system; generating the predictive output using a first trained predictive model from a repository of trained predictive models and a second trained predictive model from the repository of trained predictive models; providing the predictive output to the client computing system; and apportioning a fee received from the client computing system to generate the predictive output to a first client computing system and to a second client computing system, wherein the first client computing system provided a first set of training data that was used to train the first trained predictive model and the second client computing system provided a second set of training data that was used to train the second trained predictive model.
8. A system comprising: data processing apparatus programmed to perform operations comprising: receiving input data and a request for a predictive output from a client computing system; generating the predictive output using a first trained predictive model from a repository of trained predictive models and a second trained predictive model from the repository of trained predictive models; providing the predictive output to the client computing system; and apportioning a fee received from the client computing system to generate the predictive output to a first client computing system and to a second client computing system, wherein the first client computing system provided a first set of training data that was used to train the first trained predictive model and the second client computing system provided a second set of training data that was used to train the second trained predictive model. 13. The system of claim 8 , wherein the operations further comprise: receiving data from the first client computing system indicating that permission is granted to the client computing system for the client computing system to access the first trained predictive model.