1. A computer-implemented method of determining proportionate use of system resources by applications executing in a shared hosting environment, the method comprising: executing monitor agents, one monitor agent for one or more instances of the applications, including collecting by the monitor agents data describing each instance of use of a system resource by an instance of the applications; storing by the monitor agents the collected data in data records, each data record representing a use of the system resources by a using instance of an application, the using instance comprising an instance of an application that uses a resource as represented by a data record; and storing by the monitor agents in the data records monitor tags, the monitor tags identifying each data record and identifying each using instance of an application for each data record.