MOVE-FLOW denotes Software as a Service workflow management system.  MOVE-FLOW is a WfMS that works as a service and adopts SaaS model.  SaaS is a model of software deployment where an application is hosted as a service provided to customers across the Internet without the need to install and run the application on the customer's computer. SaaS reduces the total cost of ownership because organizations have to pay for the rent services only instead of pay for a full system license.  Also it reduce maintenance cost, where customers will not host the application, in turn they will not pay attention to maintain it.
By supporting SaaS deployment model, MOVE-FLOW will be used by organization without the need to host it on their servers.  They only need to host processes they want to execute.  The following Figure  shows how organization can subscribe and host  their process to MOVE-FLOW engine. 

Organization host their processes to MOVE-FLOW

Workflow system can be described as a cube with three dimensions Organization, Business process, and Information.  A WfMS that support SaaS will deal with multiple organizations, processes for each organization, and information related to these processes.

In turn MOE SaaS-Flow must; at least, satisfy the following conditions:
Allow organizations to subscribe to the system, and uniquely identify them.
Enable subscribers to upload and register their processes to system in a standard format.
Provide mechanism for subscribers' end users to execute processes.
Enable end users to view and execute their tasks. 

Allow subscribers to integrate their applications to the WfMS independent of their location or working environment.
Provide security mechanism to authenticate requests coming from subscribers' applications.

Guarantee isolation between different subscribers' processes and tasks. At the same time enable integration between them.
Enables subscribers to register their services.  Then attach these services to their correspondent activities.
All this points must be taken into consideration while designing a WfMS supporting SaaS.

Another working model MOVE-FLOW is trying to handle is cross-organization process.  Such process needs collaboration of more than one organization to execute and complete.  That is mean one process has to be executed over heterogeneous system environment.

An example of such process is "Employee transfer process" that executes between two governmental organizations.  Each organization has its applications and working operating system that are not the same for the other organization, but at the same time both of them are under roles and regulation of the government.  That is mean a standard "Governmental Transfer Process" should be used to manage employee transfer between two organizations.

Based on previously mentioned scenario, Interoperability and controlling application flow remotely become a great issue.  Also new problems may appear in the future, such as the need for a special type of process execution, which encourage taking into consideration the need to extend MOVE-FLOW easily.  To provide an extendable WfMS system that can face the ongoing changing in now a day environment.