1. A digital analytics system comprising: a data management system including data extraction modules and a data storage system comprising storage units; an analytics engine system hosting and executing a plurality of analytics engines, each associated with a different application, wherein each of the data extraction modules and each of the storage units are assigned to a particular one of the analytics engines and the associated application for the analytics engine, and each of the data extraction modules extracts data from at least one data source and stores the data in the storage unit for the analytics engine or the associated application assigned to the data extraction module, and the storage unit segregates the stored data from data stored in any of the other storage units, and each of the data extraction modules includes translation rules for the assigned analytics engine and the associated application, the translation rules including instructions to re-format and filter the data from the at least one data source prior to storing the data in the storage unit, and to filter the data, the data extraction module receives, from the assigned analytics engine or the associated application, a query for a data set conforming to constraints in the query, runs the query on data from the at least one data source to identify query results from the data, prior to storing the query results in the corresponding storage unit, re-formats the query results according to the translation rules, and stores the re-formatted, query results in the corresponding storage unit, wherein the plurality of analytics engines include: a workforce planning (WFP) analytics engine associated with a WFP application, and an interface for the WFP analytics engine, wherein the interface retrieves sales data from the storage unit for the WFP analytics engine and provides the sales data to the WFP analytics engine, and the WFP analytics engine estimates sales for a future time period based on the sales data, and the WFP application uses the sales estimates to estimate a needed increase or decrease in workforce and interacts with a system of a client to identify and contact a user to provide an indication of the needed increase or decrease in workforce; and a utility plant performance analytics engine, an interface for the utility plant performance analytics engine, and a utility plant performance application, wherein the interface for the utility plant performance analytics engine retrieves data from a predetermined storage unit and provides the data to the utility plant performance analytics engine, the utility plant performance analytics engine estimates a utility plant metric for a future time period based on the data, and the utility plant performance application uses the estimated metric to schedule maintenance for the utility plant, wherein the data comprises maintenance logs for the utility plant, manufacturers' recommended maintenance instructions, and maintenance logs for other utility plants, and the utility plant performance analytics engine estimates when maintenance is due for the utility plant based on the data, and the utility plant performance application provides notification to the client of the estimates for maintenance; and an applications interface and storage storing the applications, wherein the applications are executed using information generated by at least one of prescriptive and descriptive analytics performed by the analytics engines, wherein the data extraction modules further include business intelligence rules including a list of prioritized data sources, wherein the data extraction modules are to determine whether same or similar data is available from multiple data sources, and in response to determining that the same or similar data is available from multiple data sources, the data extraction modules are to use the prioritized list of data sources to accept data from a plurality of the data sources in an order specified in the prioritized list.