14. The computer program product of claim 13 , further comprising a feature manager of an online system configured to: calculate, by the computer processor, a weighted combination of feature values from the first incremental feature store, from the second incremental feature store, and from the cumulative feature store.
13. The computer program product of claim 10 , wherein the incremental feature store is a first incremental feature store, further comprising a feature manager of an online system configured to: maintain, by the online system, a second incremental feature store; mark the first incremental feature store as inactive at a subsequent time point; and update features of the second incremental feature store responsive to user actions received by the online system after the subsequent time point.