1. A system, comprising: one or more memory locations configured to provide isolated environments comprising application files and executables on one or more hosts with host operating systems; one or more servers hosting the isolated environments and their hosted applications; and one or more billing interceptors configured to: intercept access to one or more host operating system resources and interfaces; load when the hosted applications are loaded; operate at or above the host operating systems level; and load into the address spaces of each of the hosted applications without requiring any application customizations.