A workflow hosting collaborative application computing system is disclosed. The workflow hosting collaborative application computing system comprises a collaborative application able to support workflow services; workflow services supported by the collaborative application including a virtual workflow operating system and workflow management tools; one or more application programs for communicating with the collaborative application; and one or more workflow authoring tools for creating workflows. The workflow operating system includes a workflow engine for instantiating and executing instances of workflows created using the authoring tools. The workflow engine is preferably selected from a group of available workflow engines. The workflow engine includes a scheduler for scheduling workflow instance events to be executed by the workflow engine. The virtual workflow operating system also includes a base workflow host that performs transaction, messaging, notification, persistence and tracking functions.