The Web Services Module provides a means for VTS to receive Simple Object Access Protocol (SOAP) requests over a network and translate those requests into VTS procedural requests. The results of these requests can be compiled back into the SOAP message format and sent back to the remote computer.

In short, this provides a way for remote applications to make use of the VTS services you choose to provide from your application.  This may be as simple as developing remote reporting and monitoring applications or as complex as a delivery scheduling system that relies on calculations done in VTS to predict when material deliveries will be required.