While I've been learning about making and presenting panoramas, I've also observed how our viewsers interact with them. It's been painful to watch first-time panorama viewers struggle with clicking and dragging to navigate, let alone using control and shift keys to zoom. They often give up and leave the page. Ouch.
I include some text on my pages ("Navigating VR panoramas: Click and drag to move around. Shift-click to zoom in, control-click to zoom out."), but there's better ways to get the point across. There's a current thread on the PanotoolsNG Yahoo group about helping readers better understand how to interact with our panoramas.
Eric Leeman at erikleeman.com has a nice Viewing Instructions page for his viewsers. It's tightly written, and blurring the background image to make the instruction text clearer is a great touch.
Matthew Rogers at 360precision (makers of the Ferrari of pano heads) posted to the list a link for a reader tutorial he developed some years ago. This one is a little more text-based, and may not be as easy to first use as Leeman's example.
I think it's important to remember that the interactive panorama is new to many of our users. Let's help them have a good experience. These examples are good starting points.