Inverse searching refers to the DVI viewer telling Vim to display the LaTeX source file at a given location when you double-click in the DVI viewer window.
You will need to enable searching in order to use this functionality.
You will also need to specify certain settings to the DVI viewer conveying the syntax which it needs to use to tell Vim how to display the source file. In YAP, you can set this option in View > Options > Inverse Search. The Command Line field needs to be set as follows:
"C:\Program Files\vim\vim61\gvim" -c ":RemoteOpen +%l %f"
The command :RemoteOpen is supplied when you install Latex-Suite.
On *nix machines, Latex-Suite attempts to call the DVI viewer in such a way that it already knows how to communicate with Vim. If this does not seem to be working, you can use the RemoteOpen command described above.