The referenceInspector combines the "Uses" and "Where Used" tab of Autodesk® Vault®.
When a document is selected in Vault the referenceInspector provides an additional tab "referenceInspector". This tab displays in the left window the references (Uses) of the document. On the right side the documents are displayed in which the selected document is used (Where Used).
So, if you have selected a component in the left window of the referenceInspector you can see the assemblies and drawings where this component is used, without jumping back and forth in different Vault tabs.