In short, a tracking shot involves a camera following a person or an object. As long as the camera isn't locked down in place by a tripod, for example, and is following (tracking) a subject, then it's a tracking shot. For good examples of tracking shots, watch the one take episode of The X-Files or most any episode of ER. Star Wars Episode One has tracking shots galore during the pod race. And I'm sure most films have some form of tracking shot or another. (It'd make a good drinking game)